Blood Magic

Not hard to learn, but it can cost you An Arm and a Leg.

"Blood is sound, sound is words, and words are power!"

— Grimoire Weiss, NieR

Spilling of blood is a potent force in the working of magic. It may be a token sacrifice, but it may also be the loss of life that fuels the spell. Expect mages who practice Blood Magic to be portrayed as evil, or at least charcoal grey, with possible exceptions made for druidlike nature cults that may be considered amoral.

Some blood may be indicated to be more powerful than others. Common types are human blood, monster blood, the blood of royalty, the blood of a special line, the blood of an innocent, a child's blood, the caster's own blood,^note or virgin's blood. Sometimes only a single person's blood has power, and any other blood is powerless. Sometimes it also makes a difference whether the blood being used was offered willingly or taken unwillingly.

The other side of the coin is menstrual blood, which is used much less frequently but is associated with life magic when it is used. Except, of course, when it's the Menstrual Menace.

This trope is Older Than Feudalism, with blood and sacrifice being powerful magic in some of the oldest tales. A very old Greek curse was for a witch to run three times around the house she wished to curse while menstruating. Especially potent if it was her first period. It is frequently the alternative to Necromancy as the "evil magic".

Often overlaps with Black Magic, The Dark Arts and Cast from Hit Points. See also Our Vampires Are Different, Body to Jewel, and Pain and Gain.

Frequently a part of any ritualistic Blood Bath. When it's the blood itself doing the damage, you have Bloody Murder. When the magic is used to extend the user's lifespan, it's Life Drinker. When it's used to create life, it's Fertile Blood. When it's used to heal, it's Heal It with Blood. Sworn Brothers who mingle their blood and gain some kind of connection that way sometimes qualify.

May even overlap with Tome of Eldritch Lore, which is often written in man's blood on parchment made of human flesh. Is often a cause for a Superhuman Transfusion. If the blood is caused by making oneself bleed, then it's a Self-Harm–Induced Superpower.

Examples:

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Anime & Manga

In Berserk, the Behelits that summon the Godhand are activated when they come into contact with blood. This usually, but not always, happens during their owners' Despair Event Horizon, which makes them that much more willing to sacrifice the people they most hold dear to be reborn as a demon.
In Black Cat, Sheldon's Tao is manipulating blood.
Black Clover:
- The Witch Queen uses Blood Magic to control people and perform incredible feats of healing.
- Vanica uses Blood Magic, forming a giant Red Beast out of blood to fight for her and congealing blood into attacks.
In Bleach, Giselle Gewelle controls the bodies of whoever gets splattered with her blood. When a member of the 11th Division wounds her and both he and his companions have Giselle's blood on their clothes, she cheerfully forces them to commit seppuku.
- And if she can get her blood in a Vandenreich/Quincy, they literally become a corpse under her control. Candice is aware of this and prevents Giselle from doing so when she heals her amputated arm. The same cannot be said for poor Bambietta.
Nathaniel Hawthorne from Bungo Stray Dogs has an Ability called The Scarlet Letter which allows him to control his blood in various ways, transforming it into holy words. Even a little bit is enough to activate it.
In Claymore young girls are given the "flesh and blood" of yoma, so that they become superhuman strong warriornesses. However, it is questionable if it really is magic.
One of the Contractors in Darker than Black, Wei, is able to teleport away anything that is covered in his blood. This power is frequently used to create gaping holes in the torsos of his enemies. Naturally, the only way he can use this power is by carrying a knife and cutting his own wrists to toss blood on opponents. In case you couldn't tell, he's a bad guy.
Deadman Wonderland has an interesting spin on Blood Magic: the eponymous Deadman are capable of using Branches of Sin, a magic that allows them to weaponize their blood, such as Ganta's bloody hand blasts, Seiji's arm blades, and Karako's blood armor.
In Delicious in Dungeon, this is revealed as Marcille's true specialty. She can draw from an "infinite" pool of power and perform very complex, potent ancient magic, but the spells require varying amounts of blood, are very taxing in terms of mana usage and might take a light toll on her sanity (however the latter is up to discussion since rapid mana drain tends to do this).
In The Demon Girl Next Door, Magical power can be stolen from a Magical Girl through blood. It's not the bleeding that causes the loss of power, it's the power being absorbed out of blood by something dark-aligned. Even a single drop of blood in the wrong hands is dangerous.
Demon Slayer: Kimetsu no Yaiba:
- The strongest of demons are capable of using their own blood as a catalyst for their supernatural abilities, known as Blood Demon Arts.
- Muzan, as the demon king, can turn humans into demons by feeding them with his own blood.
Dragon Knights gave its Dragon Lord super-condensed Light Magic for blood that will kill on contact anyone who isn't related to him and shares his blood (and his wife, for whatever magic reason). This is something of a problem when the Big Bad curses him to bleed out slowly and can't be properly given medical treatment!
Fullmetal Alchemist:
- In Fullmetal Alchemist:
  - Ed and Al used their own blood as an ingredient in their attempt to resurrect their mother. When that failed miserably, costing Ed a leg and Al his entire body, Ed used his blood to draw a seal on a nearby suit of armor, binding his lost brother's wayward soul to it. This is justified by noting that the iron in the hemoglobin bonded with the iron of the armor, and the destruction of the bloodseal would kill Al.
  - Later, when Martel is killed while inside Al, some of her blood runs down and over Al's blood seal, making him black out. However, this also allows him to remember what happened to him beyond the Gate.
  - The transmutation circle to generate a Philosopher's Stone needs to have five "crests of blood" made from killing. For the nationwide transmutation circle, five gigantic military engagements which could be more aptly called butcherings created the five crests needed to cover all of Amestris.
- In the movie, The Sacred Star of Milos, the eponymous Sanguine Star is a Philosopher's Stone created by sacrificing the blood (not the souls) of several dozen soldiers.
- In Fullmetal Alchemist (2003), Mustang ends up creating a transmutation circle out of his own blood in order to defeat Pride.
- Fullmetal Alchemist: The Conqueror of Shamballa: The circle to open the Gate only activates when it gets in touch with blood. Edward has a little blood on his glove the first time he opens it. The second time Hohenheim gets mauled by Envy, while in Amestris Wrath dies.
Hellsing, where it is referred to as "the currency of the soul." What it means is that vampires like Alucard absorbs their meals' souls when they consume their blood. Seras discovers this truth when she consumes Pip's blood, collecting his soul, becoming a true vampire, and herself gaining some of the Power of Blood. Later, it's revealed that the huge amount of souls he's consumed fuels his absurdly powerful Healing Factor — and that he can release his victims as a macabre army of the undead. It's also stated that a person's blood offered with consent gives much more power to a vampire than blood taken from a victim unwillingly.
Mermaid Saga is referenced in Hell Teacher Nube. Here, flesh from the (still living) mermaid Hayame has a 100% success rate, and her blood can instantly heal any injury no matter how grave, without conferring immortality. It does have the side effect of making the recipient into a moron for a short while, seeing as it comes from Hayame, after all.
In Inuyasha the priestess Hitomiko is able to launch invisible blades using her shrine bells to cause blood letting wounds on her enemy which then paint a circle on the floor binding them magically. She can also cause the blood to combust.
- Inuyasha the Movie: Fire on the Mystic Island: The Four War Gods create a clone of Kikyo using a sample of her blood.
One of the ways the title character of Izetta: The Last Witch can channel her magic is through her blood. A few drops scattered on snow, for instance, can let her call forth spears of ice capable of impaling speeding fighter planes.
In Rumiko Takahashi's Mermaid Saga, mermaid flesh can, if you're (un)lucky enough to survive eating it without becoming a Lost Soul, turn you immortal. But in the "Mermaid Forest" story, all that Sawa has is a flask of mermaid blood to heal her sister's illness. It made Towa immortal, but deformed her arm like a Lost Soul's, and now she regularly replaces it with arms cut from the fresh corpses of young women.
My Hero Academia has villains with blood-related powers — Hero Killer Stain can paralyze people whose blood he ingests for a certain amount of time (depending on their blood type), while his Loony Fan Toga can shapeshift into people whose blood she ingests. There's also Vlad King, the teacher of Class 1-B at UA who has a "Blood Manipulation" quirk, but so far it's only been shown that his power lets him control his own blood, which he can eject from his body and form into various shapes.
Some of Naruto's Summoning Rituals use this.
- By drinking someone's blood and then standing on a symbol also made of blood (which doesn't have to be theirs), Hidan can turn himself into a living voodoo-doll for his opponent.
Some of the magic in Negima! Magister Negi Magi works like this. At one point, Negi bites his thumb hard enough for blood to pour out, then creates magic circles for The Thousand Bolts (the ultimate lighting incantation) and pulverizes a mountain-sized rock. Blood of powerful mages also seems to carry a certain amount of energy in it if Evangeline is to be believed. If.
The Princess Resurrection manga uses blood magic as a fairly major plot point. The anime changed it to fire/energy. The manga would also eventually use fire instead of blood, but MUCH later into story, close to the end.
In Princess Tutu, Fakir revives Mytho's Cool Sword by cutting his hand, and pouring the blood from the wound into a fountain, and reciting a spell in German while dipping the blade into the bloody water. The various applications of Raven's Blood (like turning Mytho evil) might apply here, as well. In fact, all of the "in-story" magic seems to involve blood or hearts (Kraehe presumably gets her powers from the Raven's blood in her, Tutu gets hers from the Prince's heartshard, the Raven gains power by eating hearts). Also, Drosselmeyer wrote a very powerful story in his own blood, and Fakir was only able to effectively rewrite the story after he had spilled his own blood onto a page.
In Puella Magi Madoka Magica The Movie: Rebellion, Sayaka Miki normally needs a body of water to summon Oktavia von Seckendorff, but she can use her own blood as a substitute in a pinch.
In Red River (1995), Hot Witch Nakia brings a girl from our times, Yuri Suzuki, to the Hittite Empire since she want to use her blood for a spell that will allow her to kill her stepson Kail and place her own son Juda as heir. Too bad Yuri was smarter and more willing to fight back than Nakia thought she'd be...
In Witch Hat Atelier, a criminal witch uses blood to produce magic ink needed to draw magic. It's later explained that mixing human blood with the wood-based ink that's usually used for magic causes extreme and unpredictable results, which is why witches are forbidden from partaking in combat, learning medicine, or be in any situation where blood is likely to mix with their ink.

Card Games

Magic: The Gathering:
- A vampire planeswalker known as Sorin Markov is said to use sangromancy (blood magic), which enables him to drain the lifeforce of other beings, place curses on enemies, and possess the minds of others. It is also implied that he can leech mana from opponents. How exactly he uses blood is not stated. Sorin's grandfather Edgar Markov turned himself and Sorin into the first vampires on the plane of Innistrad using a combination of sangromancy (using Angel's blood) and a Deal with the Devil.
- Long before he showed up, the ogres of Kamigawa, a Japanese-themed world, used blood oaths to bind oni (demonic spirits in this setting) to their service. This was represented mechanically by ogres with abilities that "turned on" when you also controlled a demon, and demons with drawbacks that "turned off" if you controlled an ogre.
Sentinels of the Multiverse features the Court of Blood and its various blood mage vampires. Blood magic involves the manipulation of peoples blood in order to fuel your power. Or you can use your own blood, which is more painful to you but you don't have to kill anyone. Notable blood magic practitioners in the game outside the Court include Franz Vogel, the Crimson Conductor (whose baton leads to a really bad time for the Argent Adept), Lifeline (who ironically enough starts messing with the stuff after his Heel–Face Turn), and Hermetic (a blood magic alchemist whose "bloodstone" eventually gives him a horrible experience).

Comic Books

Arawn: After becoming a living god, Arawn can use his blood to bring people Back from the Dead.
Batman: In Detective Comics #834-834, Zatanna was shot in the throat and nearly drowned in a death trap courtesy of the Joker (don't ask why he didn't just shoot her in the head). She avoided bleeding to death by using her blood to write out a healing incantation, made extra-strong by its medium.
The Blood Queen: Blood magic was forbidden in the backstory as a compromise by the high kings of man so they wouldn't have to exterminate the Mage Species. The main character herself and several other dark wizards still use it in secret, however.
Conan the Barbarian: Conan once battled a witch who used a particularly nasty curse triggered by blood. Only a single drop of spilled blood was necessary to cause her victims to age rapidly and die within seconds, leaving behind a withered corpse. The only protection against the curse were magic talismans owned by three brothers who were the witch's enemies.
Doom Patrol: Willoughby Kipling points out that the easiest and most blood-efficient way to do this is with a papercut on the page of the spellbook you're using.
Green Lantern: This is how Atrocitus created the Central Power Battery for his Red Lantern Corps. In addition, he is capable of scrying through arcane blood rites.
Hellboy: The Queen of Witches has a thing for blood:
"Now she calls herself a goddess of war, but her war has no object other than the spilling of blood. All blood. Nothing but blood. Blood. More Blood. Nothing. But. Blood. For in the end the moon will be as blood and the sea boil and the land burn."
Hex Wives: The witches' magic is based on blood. The more blood that is spilled, the more powerful the magic becomes. It doesn't matter whose blood- theirs, their enemy's, a farm animal's. Even squishing a cockroach provides a minor boost.
Lenore the Cute Little Dead Girl: Parodied when Lenore pricks her finger and spills a drop of blood on a doll. It turns out to be a vampire that was cursed to be an inanimate plaything, and her blood broke the curse. Unfortunately, he realizes he's still in a doll's body because the curse didn't break properly; she'd been embalmed.
Red Hood and the Outlaws: Red Hood's All-Swords get extra power from his blood. Or, something like that. It hasn't been explained yet.
- Minor opponent December Graystone previously used the name "Blood Mage", and continues to use his blood to cast spells.
Robyn Hood: The Big Bad in Robyn Hood: The Curse is a Mayincatec sorcerer who works his spells through the use of blood magic.
Runaways: Nico Minoru can only summon her Staff of One when she is bleeding. Menstrual blood also works in this case. It also allows her to circumvent one of the restrictions the spell has (reviving the dead) during Avengers Arena after she sheds enough.
The Sandman: In A Game of You, menstrual blood is used to power a spell to send the characters into Barbie's dream and come back alive (mostly). The spell is repeated with blood from a cut palm in Death: Time of Your Life.
Spawn: The comic features demons that need blood to power their various devices.
Teen Titans: The villain Brother Blood leads a cult who focuses magic through bloodletting (yes, he's a little different from the cartoon version). One of his best-known acts was resurrecting Raven to be his bride (it was basically the writers' way of bringing her back to coincide with the success of the cartoon).
Vampire: The Masquerade (Vault): In Vampire: The Masquerade: Winter's Teeth]], this as an ability of Primogen Calder Wendt. Since he's a Tremere, fans of the game should know that this is to be expected. However, he uses it very casually and often for his own amusement.
Wonder Woman: In Wonder Woman (1987), when Wonder Girl and Ferdiand accompany Diana into the underworld to confront Hades at Athena's bidding the Erinyes trap them both and start draining their blood into bowls, though the one with Cassie has a freak out when a taste of her blood reveals her parentage and begs for forgiveness only to be dispatched by Ares.

Fan Works

Alicorn: Blood magic has been outlawed in Equestria since before it was Equestria. By taking a sacrifice of blood from someone, the Blood Warden can place them under a Geas, which in the fic is used by a group of terrorists to make sure none of them speak when they're arrested. Twilight admits that it's a bit less dramatic than it sounds, however. The sacrifice of blood can just be a pinprick.
In The Alarmaverse fic "Alarm Clock", a dark summoning ritual is accomplished by somepony getting a bloody nose and walking to get medical supplies, dripping blood all over the long-forgotten ritual site.
In All That Glitters (Othellia), Anna and Hans exchange blood to break an enchantment protecting a cave they need to enter.
Root uses some in the Catalyst Verse after Control tortures her, killing all of Control's guards instantly and allowing her to escape.
A Certain Droll Hivemind: Misaka-11111 encounters a magician who creates a giant bird construct after stabbing herself with a knife. The Network has no experience with magic, so they are very confused.
More blood spurts from her hands than the human body has within it. It takes form as some kind of bird. It is apparently made of gold, but it drips blood. This does not make sense. The human body does not contain giant gold blood-covered birds with glowing eyes within the bloodstream. It is probably a severe medical condition. No wonder she is in a bad mood.
We cannot identify the species of bird. Some of the Network believes it to be a raven. Others believe it to be a magpie. A minority holds it to be a crow.
I have motioned that the precise species may not be important right now, but I am substantially outvoted. The Network wishes me to enquire as to the nature of the avian.
I will do so. When I have time.
Child of the Storm includes both the Harry Potter and Dresden Files variants, leaning hard towards the latter. It's not Black Magic, but it is noted as being very dangerous, because it can be used for a number of purposes, mainly thaumaturgy (everything from tracking someone to biological manipulation via voodoo doll - though hair is noted as more reliable, because while blood's stronger, it doesn't last very long), particularly by vampires: drinking the right kind of blood supercharges a vampire (particularly Grey Court), while the right kind of ritual and device can imbue them with powers from it. Said ritual is why the Grey Court has Combo Platter Powers.
In The Confectionary Chronicles, the first true ritual Hermione performs for Loki is a blood sacrifice where she cuts her arm and chants worship to Loki over a stone altar she’s assembled. She later guides Fleur in performing a more detailed ritual when Fleur asks to join her in giving thanks to Loki, but most of the time Hermione just prays to Loki with offerings of sweets and chocolates, and only performs a ritual on special occasions.
crawlersout: While Gellert Grindelwald studies magic in all its forms, there are certain magicks that not even he, a Dark Lord, is willing to practice — Blood Magic is one of them. It's a sign of desperation that he's willing to search for a master of this particular magic in order to find Fem!Harry. Even then, the guy refused to do anything for him as he felt that his expertise was unnecessary, suggesting that even he was wary of the magic he practiced.
DNMC: D'Arg is able to set his swords on fire by using his blood, which happens to be infused with Dust. What qualifies it for this trope is that Dust (apart from its canon counterpart, at least) is described as magic in "DNMC: Jeshile".
Dungeon Keeper Ami: Blood contains mana, which can be used to power magical things, as said in "A Capture", when wondering how to power something:
Blood. [...] the mana within is easily assimilated.
In the Empath: The Luckiest Smurf story "Where The Wind Carries You", which is an adaptation of the cartoon show episode "Never Smurf Off Till Tomorrow", Tapper (who appears in the place of the adult Nat Smurf among the Smurfs who were taken by the hurricane and dumped inside a volcano from which they escape) claims the blood of Jesus Christ over himself and his fellow Smurfs to protect them from the sharks that come swimming around them, ready to devour them. Whether it is because of this or what Tapper says, the sharks eventually swim away, leaving the Smurfs unharmed.
In Equestria Divided Fluttershy creates Everfree Wraiths by infecting ponies with her blood.
Escape From The Hokage's Hat has Naruto with multiple seals placed on him (by various Konoha ninja) to limit his growth. They were all made with blood. His own. After many a beating. Judging from a bit of dialogue between Tsunade and Shizune when they find out, placing a blood seal on someone is implied to be excruciatingly painful. Naruto got them between the ages of 6 and 9.
Subverted in-universe in The Dresden Files fanfic Fair Vote. The protagonist uses tea as a metaphysically symbolic substitute -– and it works.
Fallout: Equestria: The first power that the Black Book gives is a spell to turn blood into knives. This is by far the least horrible of its abilities, intended as a first taste to corrupt someone into taking more. Several characters use this power in the story, invariably to murder people painfully. Littlepip, however, realizes there's nothing preventing her from giving the blood a different shape, and mostly uses it to create artificial clots for medical purposes.
Fate of the Clans:
- To summon a Servant, blood or runic silver is used along with a relic relating to the hero in order to act as a catalyst. Runic silver is hard to obtain, so blood gets used.
- Since there's magical energy in blood, it can be used to invoke magecraft.
A Growing Affection has both the powers of the Blood Drinker demons, and Naruto's Blood Clone Jutsu.
In Guardians, Wizards, and Kung-Fu Fighters, we eventually see that Elizabeth Bathory knew this kind of magic, using it to, among other things, create weapons out of spilled blood, and protect herself from harm. Her spirit later teaches it to her fellow Ben Shui reincarnations Rasputin and Jade Chan.
In Harry Potter and the Scrambled Sorting, Blood Magic is more symbolic in nature, a single drop giving a tremendous power boost to a simple 'Lumos' Spell. It does have specialised magic that can only be cast through Blood Magic, and even the boosted Lumos is utterly ilegal in Magical Britain.
Hearts of Ice: Using blood of an ancient dragon, Shampoo and Cologne cast a spell to banish Akane from the mortal plane.
Kintaro: I'm sorry, Ranma, but all the signs point to this being a blood spell of some kind, and spells cast with blood are not only nefarious and unscrupulous in the extreme, but very hard to break.
Ranma: A blood spell? What the heck is that?
Kintaro: Just what it sounds like. A spell cast with the blood of a living creature. The more powerful the creature, the more powerful the spell. From what I can see in your aura, I would guess that the blood used was at least human, or possibly even that of a magical animal or spirit beast.
The Assassin's Creed fanfic Hellfire involves lots of this, as Malik is a blood mage.
In the Hetalia: Axis Powers fanfic Hetalia School for Vampire Hunters, most magical rituals involve this to some degree, usually using your own blood to form intricate symbols, which then casts the desired magical result.
i'm giving you a nightcall: Alchemy can only be activated by applying blood to an array. The Elrics are unique in that they need very little blood to activate an array.
In Loki: Agent of Doomgard a Mad Oracle's advice is to use Loki's own blood for tracking spells. As they're searching for alternate versions of themself this proves surprisingly effective.
In the A Man of Iron universe, there's a Valyrian ritual involving performing a Human Sacrifice with wildfire that can awaken a person's latent mutant powers. Magneto (a Blackfyre descendant) uses this at Harrenhal to give Arya and Gendry their powers, while the wildfire explosion that destroys Stannis' fleet at the Battle of the Blackwater inadvertently acts as an invocation of the ritual as well, granting powers to numerous people in King's Landing.
In A New Order main character Sailor Moon can only use her strongest spell when she is injured and bleeding. The more blood she's lost, the stronger it is.
In The Night Unfurls: Hugh's katana, the Chikage, has a rite that coats the blade with blood, extending it. It also feeds on the life force of its user and the blood of his enemies to enhance the damage dealt.
Team 7 (Naruto, Sasuke, and Hinata) aka Team Lie (and later Neji) in People Lie make a pact with Kyuubi, "Blood for power, power for blood." They deliberately sacrifice blood in exchange for power; Naruto enters his canon Super Mode whereas Hinata, Sasuke, and Neji all gain more powerful forms of their doujutsu.
In Perfection Is Overrated, Toki's Child, Cronos, has the ability to spawn black dragon minions from its own blood. She sends them back in time in order to alter Mai, Natsuki and Nao's pasts to prevent them from ever coming to Fuuka Academy, and after that plan is thwarted, sends them against the three when she faces them in combat.
Points of Familiarity:
- Shinji bites off his finger and sacrifices it to ... something to create [Masks].
- Plus, Dragon's blood and unicorn's blood both have extraordinary properties — respectively, the 12 uses of dragon's blood, as discovered by Dumbledore and Nicholas Flamel, and granting life — a cursed half-life — no matter what.
In Rabbit of the Moon, becoming a Hunter gives Bell access to the Old Blood, allowing him to greatly increase his strength and skills through the Blood Echoes of the monsters he slays. He can also ingest or inject other sources of blood to heal himself, dye bullets with his own blood to injure the monsters of Yharnam, among other things.
The Rigel Black Chronicles:
- Harry doesn't make a deep study of blood magic, but she has enough of the basics to know that it's important to carefully clean up any blood you've spilled, especially if it was done willingly, lest someone get hold of it and use it against you. Her opponent in a Triwizard duel is less careful, and pays for it.
- Two of the Triwizard Tasks demand blood payment in order to pass barriers. Turns out that Voldemort had an agent get hold of the samples so that he could use it in a ritual to steal Harry's magic. Fortunately, she was savvy enough to use someone else's blood instead of her own, making the ritual backfire.
In the Harry Potter/Disgaea crossover Something Wicked This Way Comes, Voldemort's locket horcrux is sealed behind a wall requiring blood, like in canon. Etna wonders why he didn't think to key it into his own blood, instead of making it so that anyone could enter if they cut themselves.
In A Study In Magic, blood magic is revealed over time to be a huge part of how magic really operates, particularly blood transfusions. Because of blood transfusions, John can absorb magic, Lestrade lost his magic and gets it back after he donates blood for the first time, lycanthropy is cured, and more. It also becomes the key in getting rid of Voldemort's last Hocrux.
In the Game of Thrones fanfic There and Back Again, The Stranger explains to Jon Snow that everyone has magic in their blood; most normally have enough to keep them alive, but Jon, as the Prince who was Promised, is imbued with much more power, which was siphoned away from him by Bloodraven to Bran Stark and Daenerys Targaryen. Consequently, the ritual that Daenerys enacted to hatch her dragons does not require a Human Sacrifice; Jon needs only to cut his hand and spread the blood over the eggs as they sit over a fire to hatch the dragons. Contrast with Daenerys, who had to sacrifice Mirri Maz Duur to hatch her dragons in canon.
Trolling the Toad: The fic establishes that blood magic is generally banned in Wizarding Britain. The only exception to this is the Blood Quill, which can only be used for signing magical contracts and official documents, and should therefore be highly regulated. The fact that Umbridge uses them for something as petty as a school detention is a plot point for the final act in the story.
True Potential: Hidan uses this trope more extensively compared to canon, as some of his skills post-Time Skip include turning himself into a mass of blood or use his own blood to harm his enemies.

Film — Animated

In the 2019 animated film version of The Pilgrim's Progress, Christian, near the end of his journey to the Celestial City, finds himself bleeding as he's drowning. He wakes up at the entrance of the Celestial City and discovers that it's the Good Shepherd's blood, not his own, that saved him.
In The Princess and the Frog, Dr. Facilier turns Naveen into a frog as to have an easy means of extracting blood for a voodoo talisman that turns Naveen's Beleaguered Assistant Lawrence into a copy of the prince for his own ends.

Film — Live-Action

Blade (1998): It's of little surprise that the ancient vampire artifact runs off of blood. Blade is strapped into a huge bloodletting device that causes his blood to fill up all the magical symbols below him, rather similar to the picture above.
The Cabin in the Woods a mechanism is triggered that causes blood to fill up the sigil representing each of the leads when the corresponding person dies. Or at least, when the operators think the person has died. Unusually for this trope, it's used to keep the ancient giant evil gods asleep, not to wake them up.
Conan the Barbarian (2011): Marique needs blood to perform some of her magic.
The Golden Voyage of Sinbad. The wizard Prince Koura uses his own blood to create a homunculus.
Hellboy:
- In Hellboy (2004); Ilsa and Kroenen kill their guide in order to resurrect Rasputin.
- In Hellboy (2019), the blood Nimue lost when King Arthur hacked her up is the last part of her body she needs to complete her own resurrection. Sure enough, she eventually reclaims it from the ancient tree that absorbed it upon her death, which reverts her from a disturbingly pretty Frankenstein-esque creature to, well, Milla Jovovich in all her scantily-clad glory.
In Hellraiser, blood is the only thing that will restore Frank to human from his undead form.
Jagged Mind: The reason why Alex takes blood from Billie is revealed to be for creating the time loops she's manipulated her with. Billie ultimately uses Alex's to cast her own spell which undoes these later.
Lesbian Vampire Killers: The blood of the last of the McLarens, along with a Virgin Sacrifice, is required in the ritual to resurrect Carmilla the Vampire Queen.
The Night Flier: Dees visits the grave of one of the vampire's latest victims at night time, then cuts open his thumb to smear a bit of blood on the tombstone, allowing him to see where the Night Flier is going. This warlock routine sorta comes out of nowhere, as Dees was shown to be nothing but a cynic of the supernatural before.
Pan's Labyrinth: The blood of a child is called for to open a gate, though the heroine refuses to take it. It still technically works — it just happens to be the protagonist's blood. And it would not have worked had the baby been used.
Pirates of the Caribbean: The Curse of the Black Pearl: Will's blood was needed to break the curse on Barbossa's crew. A blood sacrifice was required from every cursed pirate, but they had cast Will's father overboard before learning this, so Will's blood, as the closest living relative, was used as a suitable substitute. Once Jack cursed himself, he also added his blood to lift the curse "at the opportune moment".
Practical Magic: Sally and Gillian slice their palms and clasp hands to cure Gillian's Demonic Possession. It also conveniently works as a Curse Escape Clause.
Pulgasari: The Pulgasari starts off as a rice figurine made by a dying blacksmith that gets brought to life by the blacksmith's daughter, Ami, when she pricks her finger while sewing over it. Later in the film, she is able to revive him by cutting her arm and letting the blood drip into the pile of boulders trapping the Kaiju.
Silent Hill: Christabella unintentionally invokes this trope when she stabs Rose in the chest. The blood gushing from the wound destroys the church, allowing Alessa to enter. Then all hell breaks loose.
Sinbad and the Eye of the Tiger: Zenobia uses her blood to animated the Minaton.
In The Thirsty Dead, a cult abducts nubile young women off the streets of Manila to use their blood in the creation of an Elixir of Life.
Versus revolves around the "Blood of Resurrection", which the villain plans to use in the Forest of Resurrection to open some kind of a dark door and get "The Power". Zombies and reincarnated samurai are involved.

Gamebooks

Crypt of the Sorcerer have an encounter where you fight a trio of hostile Chameleon-men, who can ambush you from out of nowhere thanks to their camouflaging abilities. If you managed to kill all of them, you suddenly remember a legend where dabbing their blood on your face will grant you the ability to camouflage yourself, if just once, in the face of danger. It does work, but there's a chance where their blood on your skin will make you violently ill.

Literature

In Justin Dew's The Aether Cycle, Blood Magic is used to create Stephen's wand and his Pentacle.
Allie Beckstrom:
- In Magic to the Bone, this is used by Cody's captors.
- In Magic in the Blood, a villain steals some of Allie's, which seriously worries her.
Bazil Broketail: Most of the Enemy's magic, if it doesn't require killing a human or beast, involves drawing blood. The most horrific example occurs during campaining in the Ourdh Empire in book two. The Padmasan agents, aiding the Sephite rebels, sacrifice hundreds of slaves by hanging them upside down and slitting their throats, letting their blood soak the ground below, which is then used to create mud men — giant earth golems to bolster the Sephite forces and provide them with a counter against dragons.
The British warlocks in Bitter Seeds have to shed blood every time they summon the Eidolons, Eldritch Abominations that find human life abhorrent and so are attracted to the spilling of blood. It takes more and more blood to summon them each time, until British Intelligence are forced to commit major acts of sabotage against their own citizens (such as blowing up passenger trains and air raid shelters) to keep the supernatural war effort going. Worse, the more blood is spilled, the more information the Eidolons have on the nature of humanity, a necessary precursor to exterminating us.
In The Blood Ladders Trilogy shedding blood is the easiest way to transfer magic. Elves use blood for a variety of purposes, the least of which is creating and feeding magically constructed creatures such as the genets, and the locks on their cages are also opened with blood. Among humans, the Church's priests put a drop of their blood, inherited from Saint Winifred the first human mage, into the communion chalice to grant their congregation some protection from demons.
In the Chronicles of the Kencyrath with blood-binders — Kencyr who have the inherent magical ability of creating a telepathic link with anyone who's exposed to their blood, a link that is so powerful that can endure past death. Darkling Changers have a related ability of being able to take the form of anyone whose blood they've sampled. If a Changer tries to feed on a blood-binder, and the blood-binder's magic is stronger, then the Changer will be wracked by intense pain, the only known release form which is death.
The Canim ritualists of Codex Alera drain the blood from sentient beings (living or freshly dead) to fuel their sorcery. They demonstrate a wide range of abilities including summoning storms, shooting lightning bolts, conjuring flying demon-things to keep airborne enemies out of the upper atmosphere, unleashing poisonous gasses, and other similarly creepy and destructive things. The most decent ritualists, such as Marok, follow the old tradition of using only their own blood to fuel their magic, and were honored for their ability to do things like increase fertility and crop yields; the discovery that the blood of others worked just as well and could be supplied in greater quantities led to the ritualists becoming Evil Sorcerers.
- This is a severe limitation on their power, since the quantity of blood is very important. The storm that covered the Canim's invasion is mentioned as having cost millions of their own lives to pull off. For a long time after the Canim invaded no magic was used, because they had an insufficient source of it. When they started using it again it was revealed to be mostly fueled by Aleran slaves who had defected to the Canim and given permission to be drained after other Alerans killed them.
In Robert E. Howard's Conan the Barbarian novel The Hour of the Dragon, one reason why Xaltotun let his allies die.
"Because blood aids great sorcery!"
- In "The Phoenix on the Sword", Thoth-Amon, immediately on regaining his Ring of Power, uses the blood of the man he murdered for it to summon a powerful abomination against his old tormentor Ascalante.
Subverted in Count and Countess, where a large part of the story hinges on the main characters' belief in the magical properties of blood. Turns out there are no magical properties.
Cradle Series: Blood madra Paths aren't particularly uncommon, and many healers combine it with life madra to great effect. However, blood Paths have a negative reputation because the most common source of blood aura is spilled blood. Paths that combine sword madra and blood madra are often disparagingly referred to as "slaughter Paths," since that's the most common way to advance them. And it doesn't help that one of the four Dreadgods is the Bleeding Phoenix, and its cultists/victims can quickly gain a lot of power by accepting its bloody children. The specific quality of blood madra mentioned most often is that it affects living flesh with great power, but barely does anything to anything else. This makes it great for healers (blood madra breaks down damaged flesh, life madra builds it back up), but also extremely dangerous in combat against people.
Cruel Illusions: Since magic in magic users hums underneath the skin and is felt in the blood, blood letting helps to increase the abilities of its user. The more blood spilt from a person, the more powerful the spells. Eventually, it gets to a point where the magic users push themselves to the brink of death through blood letting and become immortal (their magician blood is all used up and instead they gain a hunger for the blood of others to replenish themselves, becoming vampires).
In A Darker Shade of Magic, Antari magic is more powerful than other types of magic, but requires the caster to spill some of their own blood.
In the world of Draconis Memoria, the Blood-blessed are empowered by drinking (raw or distilled) drake blood. They make up 0.1% of the global population, and can be identified by the reaction their skin has when coming into contact with drake blood – while regular tissue is burned by the substance, a Blood-blessed’s skin will instead turn a pale white. The power of a Blood-blessed depend on their proficiency with different types of blood – most will only excel in one type of power, with very rare exceptions who excel in all of them equally. Different kinds of drake blood will allow different powers to manifest:
- Drinking Green blood heightens the physical abilities of Blood-blessed to superhuman levels and stimulates their natural healing process. Small doses can be consumed by normal humans as panaceum and have been used to help cure numerous illnesses previously fatal to humanity.
- Drinking Red blood grants pyrokinetic abilities, and not of the fireball variety – a Blood-blessed full of Red can instantly ignite anything within their field of vision. This power, while useful in a fight, has found its greatest usage in fuelling the new "thermoplasmic" reactors used to propel ironships at incredible speeds.
- Drinking Blue blood grants the Blood-blessed access to a state called "Bluetrance", in which they can telepathically communicate with other Blood-blessed over massive distances, as well as recall and share their memories with almost photographical precision. However, this state also leaves their physical bodies completely defenceless and allows more experienced users to forcefully pry secrets from less practiced novices.
- Drinking Black blood grants the Blood-blessed telekinesis, which is rightly considered by many the most feared and valuable of the powers. Far from merely grabbing objects, Black can be used to completely immobilize other beings, reach into them to crush their organs or unleash waves of force which hit everything within a radius. The only downside to Black is that it drains from a Blood-blessed the fastest of all blood types.
- Drinking White blood grants the greatest power of all - the ability to accurately see the future, of oneself and the of the world at large. However, this power comes with the price of sealing the fate of any witnessed in the vision, making their future set.
In Devon Monk's Dead Iron, LeFel takes the child's blood for this.
Thaumaturgy in the Deepgate Codex books.
In Robin Jarvis' Deptford Mice: The Oaken Throne, the high priest of Hobb dips the Silver Acorn pendant in the blood of one Ysabelle's subjects three times during a sacrifice. Each time, he calls Hobb's name. This summons the evil rat god to the world. The bloodstains cannot be removed from the pendant, no matter how many times it is washed, until Ysabelle unites it with the magic of the Starglass and becomes the Starwife.
Considered highly dangerous and forbidden in Devils & Thieves, Blood Magic is nevertheless extremely powerful for the person who manages to use it. The most mild form is when two kindled with different magical abilities mix their blood, creating a bond that allows one to absorb power from the other, while the most infamous usage involves stealing blood from a user of each magic, in order to gain that ability. No matter which type is practiced, however, it is still considered illegal magic.
Terry Pratchett's Discworld parodies this with the Rite of Ashk-Ente, which summons Death. It's implied that this is supposed to require a human sacrifice and dozens of magical foci, but magical refinements mean that it's now possible with only an octogram, three small bits of wood, and 4 cubic centimetres of mouse blood.
- This is further refined to just needing the octogram, two small bits of wood and a fresh egg.
  - Of course, most wizards go all-out with the magical foci anyway, because if you're not going to fill up your ceremony with arcane gibberish and dribbly candles, why did you even become a wizard in the first place?
- A straighter example is in Carpe Jugulum, where Granny Weatherwax uses this kind of blood magic against vampires by "infecting" them when they feed on her.
  Granny: I ain't been vampired. You've been Weatherwaxed.
Malkar and Vey Coruscant in Doctrine of Labyrinths are accomplished practitioners. They have been using this to keep themselves young and vital for who knows how many years. One of Vey's many epithets is "Queen Blood."
Hurog: In Dragon Bones, the heroes find a heap of dead bodies that have visibly been used for blood magic, having runes cut into the skin. They give them a proper burial by burning the corpses and singing prayers.
In the Dragonlord series by Joanne Bertin, blood magic is frequently employed by the antagonists. In The Last Dragonlord, the Big Bad uses the lives of prostitutes to charge a magical artifact. He then sacrifices a member of a specific bloodline in order to attempt to enslave one of the titular dragonlords. In The Dragon and the Phoenix, the blood of the high priest is used to bind a dragon, and the magic of the dragon is used in turn to imprison and harness the power of the phoenix.
In Andre Norton's Dread Companion, Kilda has to bleed to get the grass that can act as a guide. She even has to pull it by the bleeding hand.
In The Dresden Files, the main character sometimes uses traces of people's blood to locate them, but it only works if it's very fresh. In Small Favor, the Denarians use the blood of an unknown person to fuel their Hellfire-powered pentagram barrier.
- Black Magic and rituals often use sacrifices of some kind, so even though using blood is not considered evil in itself, it tends to appear a lot in the bad guys' spells. Possibly the greatest display of blood magic yet seen is the Red Court's curse seen in Changes, which required hundreds of human sacrifices to energise and then a final sacrifice to target its destructive power.
- Another example is the Stone Table, which transfers power from spilled blood into whichever of the Fae courts holds it at the time. This is, on more than one occasion, a plot point - if nothing else, Summer and Winter are very finely balanced.
Egil's Saga: When Egil suspects that the horn of ale offered to him by Atloy-Bard is poisoned, he cuts the palm of his hand, carves runes into the drinking-horn, and smears the runes with his own blood. The horn breaks and the ale spills. Seemingly the blood was needed to activate the power of the runes to magically expose the poison.
The Elenium plays with this. In this case blood isn't so much magical as it is innately capable of restraining magic. The living stone Bhelliom is supposedly controllable by two rings, each of which contains pieces of the original Bhelliom stained red with blood. Later, it's revealed that blood restrains Bhelliom for a very prosaic reason: Bhelliom cannot stand the touch of iron, and human blood has iron in it.
Empire of the Vampire: Sanguimancy is the vampiric power to channel magic using blood itself, feared even by other vampires. It can be used to make the blood within both living and Dead boil, forced to bend shape and form to the will of its user and even reshape the user's own body. However, little is known for certain about it, as it is associated with the ancient, now presumably extinct Blood Esani.
This is one type of magic used in the Evie Scelan novels.
The Factory Witches of Lowell sees the trope Downplayed and Zig-Zagged. Blood can be used as a medium for magic, but the novella only focuses on spells cast with hair and saliva. Novice witch Hannah and her magic-less friend Judith debate the merits of various mediums as they brainstorm ways to enchant their looms to participate in the worker's strike; blood, saliva, hair, bone, and even shadows are all discussed before they settle on using spit to charm their looms into compliance. Judith later summarizes the talk for fellow mill worker Lydia:
"Hair is the perfect vessel for oaths of friendship and camaraderie. Blood for family. But spit... is for the passions."
The Fallen Arises: Blood Magic is the most dangerous form of magic a mage can practice, as it corrodes the physical body of users and will eventually kill them. The only exception is Mortira Greystoke, who bonded with the magic on a genetic level through as yet unknown means and is able to use it to horrifying extent.
In Dan Abnett's Gaunt's Ghosts novel Blood Pact, the witch makes extensive use of this. On both the prisoner and Maggs — she didn't realize she had gotten blood from both of them at first, but when she did, she tried to use Maggs to assassinate the prisoner.
Harry Potter:
- In Harry Potter and the Philosopher's Stone, it's revealed that unicorn blood is so potent that drinking it can preserve the life of a somebody who is already dying, but the act of taking it - which involves killing something innocent and defenceless - is said to curse the killer with a "half-life".
- In Harry Potter and the Goblet of Fire, Voldemort uses Harry's blood to reconstitute himself, as a means of bypassing Lily's protection. This later turns out to have been a horrible idea, as it makes Voldemort himself an "anchor" to the mortal world for Harry.
- And in Harry Potter and the Half-Blood Prince, one of the enchantments used to protect a Horcrux can only be lifted with blood, if only because the caster wanted to make sure no one could enter without hurting themselves. Dumbledore is actually disappointed that Voldemort couldn't come up with something more inventive.
- A slightly less literal variant of blood magic is a significant plot detail that runs through the whole series, but isn't fully explained until Harry Potter and the Order of the Phoenix. It's fairly well established that Lily Potter's sacrifice blessed her son Harry with a powerful protective enchantment. Less clear is the fact that it affects every individual who shares Lily's blood, including her unpleasant sister Petunia. With a little help from Dumbledore, Aunt Petunia's home is effectively shielded by a Voldemort-proof barrier that no dark wizard can penetrate. Well, at least until Harry turns 17 years old.
In Orson Scott Card's Hart's Hope, blood is the essential source of magic: the more precious the blood, the most potent the magic. Kill a rabbit, and you can stop a stew from boiling over. Kill a deer and be able to turn invisible. Then kill a man to get real power. In order to exact her vengeance, Queen Beauty therefore kills her own newborn daughter, which allows her to acquire powers sufficient to subdue the gods.
Mercedes Lackey loves this concept, and blood mages are frequently villains in her books.
- In the Heralds of Valdemar books, at least, it's code for Life Energy, not the red stuff itself, and taking it from an unwilling target (via torture and murder) is exclusively villainous. Good-aligned Mages and Priests can give their lives willingly to boost a spell (especially a Final Strike), and the fairly benign rituals that bind a ruler to their country involve mixing some of their blood with the soil.
- In Tales of the Five Hundred Kingdoms, blood has a few Traditional uses. Drinking a little dragon's blood gives the ability to understand animals, while mingling blood is part of the Blood Oath that makes two people Sworn Brothers. Blood and body parts from certain creatures have magical powers, and those powers are amplified if the parts were freely offered and not taken by force. Human sacrifice also has a Traditional role, especially a Virgin Sacrifice.
- In Elemental Masters, blood is part of some elemental spells — again, the less voluntary the 'donation,' the less benign the magic. There's a particularly gruesome example at the beginning of Phoenix and Ashes, where the Wicked Stepmother cuts off her stepdaughter's finger to bind her into servitude.
Rick Riordan's The Heroes of Olympus series:
- Gaea plans to use Percy’s blood in some kind of sacrifice to bring down the gods.
- Per book three, it's any one male and one female demigod. She just really wants it to be Percy and Annabeth.
Her Crown of Fire: How the headmasters are so powerful. The headmasters take samples of blood from each new student for "testing", but are actually using the magical power inherent in the best blood samples to enhance themselves with blood runes.
Her Spell That Binds Me: Dark magic is powered by killing animals in rituals. Taking blood from a person can also give a malefician power over them. However, a benevolent version is the blood bond spell, in which two people who love each other share their blood, magically binding them together and becoming Mind Link Mates that can offer mutual protection. It's near impossible to break, but if their love fades this can become a curse.
He Who Fights With Monsters: The Red Table is a blood cult that is really into blood magic summoning. Jason ends up with the Blood essence, which mostly gives him affliction-type powers that make people bleed.
Inkmistress: Asra's blood causes flowers to bloom wherever it's spilled on the ground. She can also dictate the future through writing it in her blood, though doing so costs years from her life. A person who has this ability is called a bloodscribe. Her blood is also capable of lending abilities that she possesses to other people if used for a tincture too. Invoking a manifest can be done using her blood too, rather than asking the gods, but this is dangerous. This is described as the rarest of magical gifts.
Kate Daniels draws blood wards, magic circles drawn in the caster's blood which draw their strength from the blood itself. They can also be broken by someone of similar blood, a loophole Kate exploits to her own advantage. It is also found out that she can create armor out of her blood as well as weapons, but they disintegrate within seconds. A power she received from absorbing The Scarlet Star.
King of the Water Roads — Magic "usually" takes a toll in blood and pain to cast, according to the only trained magic-user seen in the book.
Legends of Ithyria: Mardyth's blood has many magical powers. It can make someone obey her, Feel No Pain or keep going even with mortal wounds when drunk, along with masking their presence and protecting against Magic Fire.
A Mage's Power: Members of the Bladi Clan have a unique branch of magic that uses their blood as its catalyst. The blood of anyone else is useless for magical purposes.
In the Malazan Book of the Fallen, blood magic is the eldest form of magic. It goes back way before the Warren system was established by Elder God K'rul, the Maker of Paths — which, ironically, was done using blood magic, and the Paths of Magic called the Warrens are technically his veins and the magic they provide is technically his blood. Additionally, K'rul himself and the other Elder Gods need prayer badly in order to continue existing, and that prayer needs to be provided in the form of blood sacrifice.
In Malediction Trilogy witches can use blood to perform more powerful, dark and dangerous spells. It is also the only kind of magic that works on troll — provided they use troll blood to power the spell.
The Misenchanted Sword: The Sanguinary Deception, the spell the wizard casts to make him and Valder appear dead, requires a bit of blood from them both.
In Teresa Frohock's Miserere An Autumn Tale names written in blood are particularly potent magic.
In The Mists of Avalon, Morgause is a practitioner of blood magic, killing dogs, pigs and eventually a servant in order to raise enough power to telepathically control people. She mentions that there are alternative methods, but they involve prayer and meditation and take far too long for her liking.
In Mistborn, Hemalurgy is a magical art that involves killing a victim with a metal spike, drawing some aspect of their being into the spike (like strength or intelligence, but it's normally used to take whatever magical abilities the victim may have), and then stick that spike into yourself to imbue yourself with the stolen aspect. The precise composition of the spike and where it is stuck in the recipient's body determine precisely what qualities are transferred. Strictly speaking, the position of the spike on the victim's body is also significant when stealing powers — it's just that through the heart works the best, and is generally lethal. Since it works by stitching a piece of someone's soul to your own, it damages the soul of the user and makes them more susceptible to magical mind control. Unlike its sister Arts, Allomancy and Feruchemy, Hemalurgy isn't an inborn ability but can be used by anyone with the right knowledge; Word of God indicates that this applies not just to Scadrial, the planet where Mistborn is set, but to everyone in The Cosmere, the wider universe containing a few other series by the same author.
- By the time of Wax and Wayne, the sequel series to Mistborn, all magic has been disseminated to the common populace — except Hemalurgy, which Harmony and his Faceless Immortals keep very secret. In Shadows of Self, Wax ends up with Spook's personal journal, which details Spook's careful study of Hemalurgy following Harmony's restructuring of the world.
This can be found more often in The Mortal Instruments.
- The blood of the angel Raziel has the magical effect of transforming a human into a shadowhunter.
- Jace and Clary have special powers because, through the experiments that Valentin did with them, they have more angel blood in them than other nephilim.
  - And because Simon, who was a vampire, drank the blood of Jace, he was given the ability to walk around unscathed throughout the day.
- Through another experiment by Valentin, Johnathan has demon blood in his body. Because of this, he was corrupted into evil. However, he was also able to destroy the shields of the sacred city of the nephilm.
- The blood of warlocks and fairies has a strange effect on vampires, even if it is never explained exactly what effect it is.
- In the sequel The Dark Artifices, the Big Bad for a special ritual needs the blood of a member of the Blackthorn family.
- In addition, this book also explains that only someone who has fairy blood in his body (including half-fairies) can enter the fairy realm at any time. It also seems to work with a special amulet.
- It is believed by the shadowhunters that all ordinary humans who can see the magic, have this ability because one of their ancestors was a fairy, and they still have some fairy blood in their bodies.
The Dark Ones' tunnels in Murderess open when the person entering spills blood, either his own or someone else's (or even an animal's), on a stone slab next to the entrance.
In New Arcana, only people with mageblood can use arcane magic, and mageblood is a street drug. The Order's soul-binding ritual involves mingling the blood of the cohort members.
Dead Lies Dreaming: A "pentacle scribed in goat's blood" is mentioned as one part of making a curse.
In Nightrunner Necromancer's combine Blood Magic with more traditional Necromancy, as well as Summon Magic, to do some truly scary things to the living and the dead alike.
In the Night Watch (Series) universe, the lower levels of the Twilight will quickly drain your energy; if you need to get out fast, spilling blood will do the trick.
The Obsidian & Blood trilogy takes place in the Aztec Triple Alliance at its height. Almost all magic is blood magic, ranging from simple self-sacrifice by cutting the earlobes, to animal sacrifice, to outright human sacrifices.
Oddly Enough: In "The Language of Blood", the main character is chosen to become the newest Speaker — a vampire who, when they drink blood, goes into a Fit of Prophecy that lets them learn the necessary information to keep their country prosperous, such as what their enemies are doing.
Of Fire and Stars: Queen Invasya used a blood ritual to gain her magic, rather than having made a bond with a god. This set a precedent-her people started doing it widely, and not worshiping the gods at all.
In the Old Kingdom trilogy by Garth Nix, the power of the Charter that gives the King, Abhorsen, and Clayr their unique abilities is found In the Blood — as in, both genetically and literally. Charter Stones, which keep the magical Old Kingdom sustained, can be broken if a Charter Mage's blood is spilled on them (in death), and the Great Stones can only be broken by the blood of one of the Charter bloodlines (see above.) Finally, in Abhorsen, Sam makes a sword to break apart the Eldritch Abomination by combining, among other ingredients, blood from carriers of all ~~three~~ four bloodlines.
In Stephen King's On Writing, he describes some symbolic associations of blood with life and death, sin and redemption (through sacrifice), and how they're used in Carrie as a parallel to the titular psychic's emerging powers and rampage.
In The Orphan's Tales, starlight is really a blood of the sky and can be used to perform some kinds of magic, like Shapeshifting.
In Overlord, Shalltear Bloodfallen gathers the blood of her victims into an orb that hovers above her. She can use the blood as a substitute to mana, or she can bathe herself in it to drastically increase her strength at the cost of becoming uncontrollable.
In Pact, blood is symbolic of the self, and can therefore be used as a source of power in an emergency-but only the mad or the desperate do this, because spilling blood is spilling the self, and a lot of Others like it when people are hollowed out shells-it gives them room to move in.
The Path Of Ascension: Blood is simply one of dozens-to hundreds of elements that one can specialize in, but outside of healers, most people who specialize in Blood magic tend to be rather unsavory, a fact that causes Liz (who is locked into blood magic thanks to her Talent) no small amount of distress.
The Paper Magician has Excision, the magic channeled through human flesh. Blood is included, and seems to be the most frequently-used component. In the first book alone, we see blood-fueled spells to blast enemies backwards, teleport, divine someone's location, instantly heal bullet wounds, control the movement of blood-tainted water...the list goes on.
Tamora Pierce makes use of this both in Circle of Magic and the Tortall Universe. However, it is made abundantly clear that the only approved use of blood magic is when the mage uses his or her own blood.
- A specific version of it can be found in The Immortals. As proved with Cloud and Brokefang, any animal that ingests Daine's blood becomes very special and more like humans in thought.
- The Bazhir tribes in Song of the Lioness have a spiritual leader known as the Voice of the Tribes, who all adults are magically linked to. Becoming the Voice involves mingling blood with the previous Voice by cutting both's arms and binding them together. Alanna also fuses her broken sword Lightning with Roger's crystal sword in a ritual that involves cutting her forearm, and muses that she's vain enough to not like acquiring fresh scars but has accepted that that's just going to be a part of her life.
- In the fourth book of The Immortals Ozorne uses his own blood to create Blob Monster spies known as darkings. If they had been created in the mortal realms they would have been innately loyal to him, but because he worked in the Divine Realms he keeps them in line through torture, and they start to turn on him after Daine shows them kindness. When a pair try to help Daine in her final battle against him, though, he's able to turn them back into blood. Darkings as a species survive to be part of the Trickster Duology and Tortall and Other Lands.
- Speaking of Tortall And Other Lands, in the short story Huntress, Corey prays desperately and clutches her Goddess pendant hard enough to draw blood while being pursued by the Pack. Since her family had also served Her diligently for generations, She accepts this as an invitation and kills all of the Pack to save Corey.
A Poison Dark and Drowning introduces a spell that can dispel Glamours. By taking a thread and wetting it in blood, one says the incantation and swipes at the glamour with the stave, slicing through it. Henrietta makes use of it to dispel the glamour around Ralph Strangewayes' house.
The Power of Five: One of the things required to open Raven's Gate is Matt's blood, exactly the reason why he was adopted by Mrs. Deverill.
In A Practical Guide to Evil this is pretty much the signature art of the Always Chaotic Evil Praesi, and especially the Soninke Lords. In the Dread Empire of Praes, criminals convicted of capital offences are auctioned by the state, and are purchased by the High Lords for 'field rituals' to boost the crop yields. In a twist, it's not done For the Evulz but because without the field rituals the Dread Empire would starve
- The Dread Empire isn't the only wielder of Blood Magic, buy it is the most experienced. When one of the other evil powers enacts a ritual a (rather shaken) hero notes that the Praesi would have only used half the sacrifices although as this is the Tyrant, it's entirely possible he upped the body count purely for the sake of it
- It's also used for healing purposes, when injuries exceed what Healing Magic can offer.
Princesses of the Pizza Parlor: Appears to be the defining concept of witch magic:
- From Princesses Don't Do Summer School: From witch Princess Bianca of a family of witches:
  This is a spell that Gran'Mama taught me, so be quiet before I chicken out. [...] she stabbed her thumb with the pin. A single drop of blood was squeezed out onto the paper.
  [...]
  Cassie, who was staring at her. [...] "W... w... that was witchcraft!"
- From Princesses in the Darkest Depths: With some Palm Bloodletting:
  This was perhaps the witchiest thing she'd ever done [...] she took her personal knife and ran it over the palm of her hand.
In L. Jagi Lamplighter's Prospero Regained, blood can give power and life to those in Hell. Kinda awkward when hellish mosquitoes have figured out you are alive and so have blood.
In The Psalms of Isaak, Blood Magick is the in-universe term for magical potions or powders that must be distilled from human blood (as opposed to the more common Earth Magick, which is created from naturally occurring compounds in the stone and soil). Blood Magick is usually extremely powerful, but can also be extremely hazardous to the user's health, and is considered a Dangerous Forbidden Technique in most of the Named Lands, though The Empire of Y'Zir uses it heavily (and has a religion based around it). Like most magic in the series, it's mostly used to enhance the user's physical abilities, but can be used to produce more spectacular effects through an unrevealed process — the Seven Cacaphonic Deaths of Xhum Y'zir, the most powerful and destructive spell ever created, is said to be a product of Blood Magick.
Early in The Red Tent, it's mentioned that Rachel's first menstrual blood was collected and used to fertilize the crops, on the belief that menstrual blood from a virgin makes food crops grow bigger and stronger. Interestingly, there is some truth to this, in that blood is rich in nitrogen, which does make it a good fertilizer, as any organic gardener who has ever used blood meal can tell you. However it does not have to be menstrual blood, and it does not have to be from a virgin (male or female). And it doesn't even have to be human blood. (The aforementioned blood meal, for example, is a byproduct of meat-processing.)
One of the spells granted to Naofumi in The Rising of the Shield Hero by the Wrath Shield is called "Blood Sacrifice". The spell violently pulls out much of Naofumi's own blood to summon a giant maw of fangs to bite down on and crush his victims to death. The backlash is so severe that it takes him an entire month to recuperate not just from the blood loss, but from the potent curse seeping his body.
The Saga of Hrolf Kraki: After Moose-Frodi has tested the strength of his brother Bodvar by shoving him and found that Bodvar is not as strong as he, he cuts himself in the calf so blood comes out and makes Bodvar drink it. He then tries again to shove Bodvar and is pleased when Bodvar does not budge, affirming that drinking Frodi's blood has made Bodvar stronger.
In the Schooled in Magic series, blood is used in many aspects of magic, but not commonly. It can be used to power ritual magic, to steal magic through necromantic rites, or to help target a spell on a specific individual.
In Holly Lisle's The Secret Texts trilogy, each of the three schools of magic use blood/flesh sacrifices. The origin of these sacrifices reflects where the magic lies on the good to evil scale. Falcons use their own blood and are good. Wolves use others present at the time as a sacrifice and are bad. Dragons are able to use whole populations at a distance as their sacrifice and are Super Scary Evil.
In Shadow of the Conqueror, sunforging an item requires a sample of blood, with the resulting sunucle being linked to the person who provided the blood.
The Mosquito-kinden of Shadows of the Apt have a serious thing about blood, and huge quantities turn up in some prophecies.
In Shaman Blues, blood is the carrier of magic, so sacrifices are made to obtain the power hidden within it.
The blades that provide the name of The Sharing Knife series are carved from the bones of the local Mage Species (thighbones, by preference) and driven into living hearts to empower them for the purpose of slaying the 'Lakewalker's' enemies. The Lakewalkers are in fact the good guys, the things they hunt will kill everything if even a single one is left unchecked, any every other weapon just gets the latter's attention.
At the start of the Shattered Twilight story The Farmer's Wife, the eponymous wife uses a sacrifice of her own blood as part of a ritual to summon a demon.
Shatter the Sky: Maren is bonded with the old mother dragon Naava through drinking Naava's blood with her own shed into a fire near her.
A Song of Ice and Fire:
- Blood magic is, in general, one of the more effective, powerful, and, according to many, dangerous magics known in the Song of Ice and Fire universe. Maegi have been known to predict accurate prophecy by consuming blood, and the burning of blood, body parts, and people (often in sacrifice to gods) is effective at accomplishing various magical tasks. There are also some basic rules; most prominently, only death can pay for life. Also mixed with a shockingly big cautionary notice, namely "buyer beware": define what you mean and want very carefully, since both death and life have shades of meaning, and wishes can get twisted, however much blood is spilled.
- Melisandre uses blood magic to cause the death of Renly Baratheon. She also claims credit for the deaths of Robb Stark, Joffrey Baratheon, and Balon Greyjoy, but whether that's truth or fiction is very unclear at this stage. King's blood is her preferred type, and she uses a very broad definition of "king"; the blood of illegitimate children seems to work just as well as legitimate, the blood of the self-appointed King Beyond the Wall of the wildlings works as well as that of hereditary southern kings. Taking enough blood to kill the donor works better than extracting a non-lethal amount via leech.
- The maegi Mirri Maz Duur also uses blood magic to "heal" Drogo and the favor is returned by Daenerys when she burns the maegi alive as part of the magic to awaken her dragons.
In Lois McMaster Bujold's The Spirit Ring, many spells involve drawing diagrams on the ground with chalk. But one especially potent spell (for animating metal statues by investing them with the spirit of a dead animal—or a dead person) requires the caster to draw the diagram in blood (and it must be their own blood).
"The Staff in the Stone" by Garth Nix: Magical Society outlaws blood magic because it requires the painful sacrifice of a disproportionate number of lives for even minor effects, and because wizards who can stomach doing that sort of thing to animals usually turn into The Sociopath and graduate to Human Sacrifice.
In Stardust, the witches use the hearts of living stars to prolong their youth as a form of blood magic.
In Star Wars Legends, a Sith's holocron could only be opened by spilling a large amount of blood from an intelligent creature on it, so much blood that it would not survive. The Jedi who finds it outwits the Holocron by pouring small amounts of their blood on it and three other people. Later, he notes that the Sith was so evil that he never even thought of this.
Also from Sword of Shadows, it's possible for weaker sorcerers to enhance their powers by draining blood from a properly bound stronger sorcerer. Penthero Iss demonstrates both the binding and the bloodletting in Nightmare Fuel detail.
Sword of Truth:
- Darken Rahl uses a kind blood magic in the form of consuming the brains and testicles (Squick!) of a young boy loyal to him to transform said boy into a creature of the underworld to ride, and thus can travel anywhere very quickly.
- Also, blood is noted as being particularly potent for drawing spell forms (alongside other things, like sorcerer's sand), though it's trickier for lasting spell forms as blood will eventually dry out and thus weaken the spell. The People's Palace in D'Hara is a spellform^note that manages to get around this through the novel method of leaving the blood inside people. The blood therefore is always fresh, and people are always allowed to travel through the halls of the palace, keeping the spell very powerful; just blood would have dried out and lost its effect long ago.
In Tales of Kolmar demon-summoning mages and those aligned with them always have to give the demons some of their own blood. On the heroic side, a mage discovers that when she touches her own blood to a dragon's soulgem her demon-fighting powers are greatly enhanced, to the point of being able to dispel minor ones with a touch.
Third Time Lucky: And Other Stories of the Most Powerful Wizard in the World: In "And Who Is Joah?" Magdelene crafts a Tracking Spell Zayd can use to find Joah in the Netherworld by using the bond of their shared father's blood. It appears like a red line stretching away before him.
Torture Princess: Fremd Torturchen: Demon magic is functionally what Charles Stross termed "algemancy": mana for spells is generated through inflicting pain on others.
- After being fed demon flesh by her Evil Uncle Vlad, Elisabeth Le Fanu gained this ability, eventually butchering the entire population of her hometown in an orgy of violence that transformed her into a being called the Torture Princess—ironically gaining the ability to generate her own mana without needing to torture people.
- In volume 3, Kaito Sena figures out that the victim of torture doesn't actually need to be human to generate mana from it. He's able to generate sufficient mana to power his contracted demon for that volume by brutalizing another demon's contractor.
In The Tower and the Fox major spells such as binding demons require additional sources of magic beyond what a sorcerer can call up from the Earth, like magically-charged blood. So English sorcerers in the 15th century bred Half Human Hybrids to act as donors for blood magic.
The Traveler's Gate: Ragnarus works on pain and sacrifice; blood is the most common medium of gaining what you want. The Hanging Trees that require nine lives every year are the most famous, but even entering the Crimson Vault requires a Ragnarus Traveler to give up some blood.
In Ruth Frances Long's The Treachery of Beautiful Things, the Woodsman and the Goodwife use blood to tame the redcaps.
The bloodline of Celtic god Cernunnos gives his descendants magical abilities they can use against him in Urban Shaman by C.E. Murphy.
Appears frequently (of course) in Warhammer 40,000:
- In Graham McNeill's Ultramarines novel Warriors of Ultramar, the Ultramarines contact another Chapter, the Mortifactors, and find their use of Blood Magic rather abhorrent.
- In Dan Abnett's Horus Heresy novel Legion, the Black Cube is activated by Blood Magic, which explains a ferocious attack on the Imperial forces: to shed lots and lots of blood.
- In Lee Lightner's Space Wolf novel Sons of Fenris, Cadmus uses Blood Magic, killing one of his officers who's guessed too much, to open a portal.
- In James Swallow's Blood Angels novels (double of course):
  - In Deus Encarmine, a knife tastes Rafel's blood and sends it back, and a Word-Bearer, by tasting it, can judge his age.
  - In Red Fury, the blood in the Bloodfiends gives them memories of those whose blood they drank, driving them crazy, Split Personality style — and with a fierce desire to drink more blood, worsening the problem. Rafen, fighting one, can clearly recognize the source of its blood, and dying, it might have said, "Brother."
- In John French’s Thousand Sons novel Ahriman: Unchanged, the Oathtaker uses the blood of sixty-four slaves to magically project his consciousness across time and space in order to confront Ahriman on Prospero.
- In Andy Hoare's White Scars novel Hunt for Voldorius, the Alpha Legion uses this. The White Scars find bodies drained of blood.
- A general example throughout the entire franchise is, oh, roughly half of everything the Chaos faction ever does. "BLOOD FOR THE BLOOD GOD" is, after all, one of their favored battle-cries.
In The Wheel of Time series by Robert Jordan, we have the mindtrap; similar to a phylactery. Combined with the blood and saliva of a channeler (magic user), it captures the soul, or essence of said channeler. Should this fragile item be crushed in someone's hand, the holder will have complete control over the (now)mindless puppet.
Something Dark and Holy: Tranavia use blood in their various rituals and spells. It's gotten to the point that even common folk can use it for simple tasks like fishing and sewing and the entire culture and society of Tranavia is supported by blood magic.
In The Witcher, one of the huge plot points concerning Ciri is that she is a direct descendant of Lara Dorren, incredibly powerful elven mage and wielder of Aen Hen Ichaer (AKA The Old Blood), power allowing her to be an independent source of magical energy as well as creating interdimensional gateways. Ciri was carefully crafted by strategic marriages, so that she gets both genes important to the Hen Ichaer — one inherited only by women, and one inherited only by men - and yes, it means incest. Taken even further by Vilgefortz of Roggeveen, a prodigious mage who turns out to be the Big Bad. He concludes that, since blood is the carrier of power, he can just take the blood. So he intends to impregnate Ciri, abort the pregnancy and inject himself with the placenta blood. The books don't state explicitly whether that would've worked. Later explained that the reason why Aen Hen Ichaer comes from elves is that elves come from another dimension in the first place, and genetically engineered the Old Blood using magic to escape their dying world.
In the Young Wizards series, healing spells require blood (that isn't from the patient), usually the healer's own blood.
- In a more aggressive case, this is the reason why the Master Shark has been around since (practically) the dawn of time. If his blood is spilled, every shark in the world is drawn to his location and is sent into an extreme feeding frenzy. Nothing dares attack him.

Live-Action TV

Angel:
- In "Sacrifice", a demon from another dimension tries to contact Jasmine with flesh magic. It's even nastier than it sounds.
- Angel is temporarily made stronger after he drinks the blood of Hamilton, the Senior Partners' liaison, in "Not Fade Away". As he remarks, Hamilton, who had been throwing him around until that point, really should not have boasted that the power of the Senior Partners flowed in his veins.
- Spoofed in "Reprise" where two Wolfram & Hart employees are following a list of instructions for a goat sacrifice.
(reading from a booklet) "Make sure all troths are securely fastened and sacrifices tilted as shown in diagram F-12 to ensure full drainage into sacred offering bowl. Using a clean, diagonal motion, slit throat of sacrifice with the pre-blessed ceremonial dagger provided... I didn't see that in the box."
Buffy the Vampire Slayer:
- In "The Gift", Dawn's blood is used to open a portal. The emphasized plot point that Buffy and Dawn have the same blood is the key to allowing Buffy to save the world. The trope is specifically lampshaded by Spike in the same episode.
Xander: Why blood?
Spike: Blood is life, lackbrain. Why do you think we eat it? It's what keeps you going, makes you warm, makes you hard, makes you other than dead. 'Course it's her blood.
- In "Becoming", Angel uses his blood to open a portal, and is later needed to close it again.
- In "Fear Itself", a stray drop of blood unwittingly opens a portal to let a fear demon possess a house. Granted, this was because it landed on a meticulously drawn summoning circle that the drawer thought was just a neat design.
- Blood of a Slayer, if drunk by a vampire, gives the latter great powers and Nigh-Invulnerability for a while. In "Graduation Day Part 2", this is used to heal Angel.
- Willow uses deer blood in her magic to resurrect Buffy. Specifically, she sits by a creek until a baby deer comes along, before she draws a knife and kills it for its blood.
- In Season 9, Willow cuts Connor's chest with the scythe to use his blood to tear a hole in the fabric of reality.
  - She also uses Buffy's blood to restore Dawn, who had been fading out of existence with Seed broken.
- In "Conversations With Dead People", blood opens the Hellmouth. Acting on the orders of the First posing as Warren, Andrew kills Jonathan to try this. Except it doesn't work: Jonathan is anemic.
- In the Master's first attempt at an early parole in "The Harvest", The Dragon Luke volunteers to become the Master's "Vessel", supplying him with power by feeding on human blood.
- It's Buffy's blood which ultimately allows the Master to break free. ("Prophecy Girl")
- In "When She Was Bad", the Master's acolytes attempt a ritual to bring him back to life. This involves slitting the necks of his adversaries (i.e. the Scoobies) and wetting his skeleton with their blood.
The girls in Charmed occasionally use blood in their magic. They used their own blood to summon their ancestor Melinda Warren, and some vanquishing potions only work when they include blood from the demon being vanquished (though sometimes other parts work, such as the dragon's scale, so it's not specifically blood).
Doctor Who: In "The Christmas Invasion", the alien Sycorax use "blood control" to hypnotize a third of the population of Earth. Technically it's Magic from Technology, but one of the UNIT characters commented that it appeared like they were casting a spell. The Sycorax reverse-engineered their technology from invaders, and think of it as magic. ("Sycorax" comes from The Tempest, where it is given as the name of a dead witch, late mistress of the island and mother to Caliban.) Though as it turns out this isn't near as impressive, or useful, as it sounds.
10th Doctor: "Cheap bit of voodoo. Scares the pants off of you but that’s as far as it goes. It’s like hypnosis. You can hypnotize someone to walk like a chicken or sing like Elvis, you can’t hypnotize them to death. Survival instinct’s too strong.
In Friday the 13th: The Series, almost every single one of the cursed items must be powered by a death to derive their benefits.
Game of Thrones:
- Mirri Maz Duur knows it, calls it by name, and warns Dany that it has a terrible price.
- Melisandre uses it to (apparently) kill Stannis' enemies, though the circumstances surrounding their deaths are sometimes ambiguous.
- The witch Maggy, who predicts Cersei's future in "The Wars to Come", needs to taste her blood to do so.
- Shireen is sacrificed because of her king's blood in an attempt to end a blizzard.
H₂O: Just Add Water offhandedly confirms that hydrokinesis can be used on people's blood when the girls have to resuscitate Miriam after Emma accidentally flash-froze her, and Cleo is asked to get Miriam's blood flowing again.
- Mako Mermaids: An H₂O Adventure: Zac, Ondina, and Erik have all demonstrated a willingness to bloodbend other people, either out of desperation or as an intimidation factor.
Iron Reign: The santero whom Ariel sees cuts his hand to get some blood as part of a ritual. He later sacrifices a chicken in the ritual too.
Legend of the Seeker
- The journey books need to use blood as ink to work. Rahl apparently likes to use the blood of people who've failed him. This wasn't the case in the original books (though they have their own examples of Blood Magic, seen above), where the journey books used the same ink as any other book.
- The Keeper also uses it to create banelings, who stay alive only if they kill someone every day.
- In an Alternate Reality Episode the Sisters of the Dark use Jennsen's blood as an Anti-Magic potion so they can get past the spells protecting the People's Palace.
Lovecraft Country: Christina uses Atticus' blood to fuel a spell, which would be fatal. Thankfully, she gets stopped.
Merlin:
- Blood magic shows up in one of the spells of Nimueh in Season 1.
- Later, Morgause uses the Cup of Life to create an immortal army by filling it with blood.
October Faction: Alice's ability to make people shoot themselves and others against their will is called this.
Once Upon a Time (2011): "Blood Magic" as a concept shows up often, typically referring to magic barriers that can only be broken or accessed by the magic user who created it (or a blood relative). Blood being an ingredient is far less common, though it has been used, most notably in tracking spells and by Gothel in season seven, as she needs the blood of the two people her daughter loves most (her father and the woman she loves) to enact her final spell.
In the third season of Penny Dreadful, Hecate uses Ethan's blood in a spell that summons rattlesnakes to attack their pursuers.
In Salem, this appears to be the basis of the "grand rite" the witches plan, requiring the deaths of innocents condemned as witches. Blood and death are two of the hallmarks of witchcraft.
Shadow and Bone: The offensive application of Heartrender abilities — they can control opponents' circulation to incapacitate them. Season 2 reveals that particularly powerful Durasts can do something similar by manipulating trace metals in the blood.
In Star Trek: Deep Space Nine when Kai Winn is attempting to read the Book of the Pah-wraiths (essentially the Bajoran Necronomicon) it appears to her to be a blank book. Another priest catches her at it, is horribly shocked at finding his superior (essentially the Pope of his world) doing such a thing, and starts to run from the room to denounce her to the other priests. She picks up a letter opener and stabs him; his blood falls on the book and... what do you know, the writing becomes visible.
In Supernatural has many:
- Azazel's lackeys used a squicky blood fueled ritual to communicate with him. This is done by the lackey draining a victim's blood into a special goblet, which lets them speak through the blood to Azazel. Brady does the same to communicate with his master, Pestilence.
- And the Special Children got their powers from Azazel bleeding into their mouths. Sam later learns that he can increase his powers in direct proportion to how much demon blood he drinks. It's also highly addictive, with a horrific and torturous detox process.
- And in the fourth season finale, it turns out the blood of the first demon, Lilith, must be spilled to complete a ritual to release Lucifer from Hell.
- In the fourth and fifth seasons, blood can be used to construct a sigil that will temporarily dispel an angel from the area.
- Season five reveals that Sam addiction to demon blood was deliberately engineered by the forces of Hell, because demon blood can strengthen the human vessels of archangels, and keeps them from exploding from the effort of containing said angels. Castiel offhandedly mentions that Lucifer is forcing his current victim, Nick, to drink gallons of it on a regular basis, but it can only do so much because Nick isn't the true vessel, and he's currently "wearing thin".
- A season five episode had Sam, Dean and Gabriel bound to a location via blood.
- The sixth season finale had the gate to Purgatory open using a cocktail of virgin blood and blood from a Purgatory resident. They are really fond of this trope.
- In Season 9 Abaddon's followers do some kind of cutting ritual to repair her meatsuit's heavily burned body.
On Teen Wolf, this is a way for a Druid to attain increased physical and magical powers. Human sacrifices, selected because they possess a specific defining feature (e.g. virgins, warriors, healers, philosophers and guardians) are ritualistically murdered for this purpose.
Tidelands (Netflix):
- Adrielle has a seer she keeps as a prisoner whose blood when dripped in the water allows them to have clairvoyant visions.
- Colton is sacrificed on Adrielle's orders, with his blood shed in the sea summoning a siren briefly.
Two Sentence Horror Stories: In "Manifest Destiny" Jeremy cutting his hand on the Sheriff's tombstone brings his spirit up somehow.
In the first episode of Warehouse13 the first artifact we see is a Mesoamerican statue (looks like a stone jack-o-lantern) that possesses a man when he accidentally cuts his finger on it.
In Xena: Warrior Princess, the evil god Dahok requires the loss of "blood innocence" to bring forth his evil offspring, so his followers trick Gabrielle into committing murder. In this case, it's the loss of life that fuels Dahok's power, but Gabrielle's hands are also covered in blood.

Myths & Religion

The Bible:
- The Jews annually sacrificed sheep and doves as "pure" sacrifices to God in exchange for atonement for their sins. The book of Leviticus especially goes into detail about the use of animal blood in these temple rituals.
  - For Christians, this is taken as a foreshadowing for Jesus's sacrifice during the crucifixion, using himself as the ultimate pure sacrifice to nullify everyone's sins permanently, which is why Christians don't sacrifice animals anymore.^note
- The Passover where the Angel of Death came to kill the firstborn children of Egypt, and the Jews painted their doors with lamb blood so the angel would know not to kill those firstborn children.
- Christians still have the metaphorical (or literal, depending on if you believe in transubstantiation) use of Jesus's blood in the Communion ceremony.
In Pentecostal and Charismatic circles, the spurious Scriptural practice of "pleading the blood" that takes place within their meetings, since they believe that Jesus Christ's pure sinless blood has actual supernatural power over all things earthly and supernatural.
The mythical account of Shaka Zulu. In exchange for limitless power, Shaka is said to enter a pact with the witch doctor Issanoussi, who demands the death of Shaka's pregnant fiancée Noliwe — and this turns out to be just the down-payment for "blood medicine":
"The medicine with which I inoculated you is the medicine of blood; so if you do not spill blood in abundance, it will turn against you, and it is you whom it will kill" (Chaka the Zulu — Thomas Mofolo)
Mesoamericans in general thought the gods needed to be fed with blood. Bloodletting was common during religious ceremonies, and Human Sacrifice was a way to offer blood (in addition to other uses)
- Aztecs thought their sun god needed to be fed with blood to continue across that sky. Cue Beat Still, My Heart.
- Mayans record bloodletting by nobles/rulers in several ceremonies. This may have been used to see visions (from blood loss), in addition to feeding the gods.
In some parts of the West Indies, it used to be common to use animal blood at a boat's launching ceremony. Squeamish Americans and Europeans just use champagne, the wusses.
- A common story from the German and Dutch North Sea coast is that in the past people made live sacrifices when building dikes against floods. Burying a dog alive under the new dike would work, but a human child was considered preferable. The important part was, that a living thing had to be given to the spirits.
- Similar stories in Great Britain were told about human sacrifices being buried in the foundations of buildings. Actual skeletons have been found under Stonehenge, proving something like it did happen at least in some cases.
  - Unless, of course, the purpose of Stonehenge was, like the pyramids of Egypt, to be a burial site for people of importance. But where's the fun in that?
The polong from Malaysian Mythology is a spirit created by chanting spells over the blood of a murderer in a bottle for a period of seven to fourteen days. After creation, it has to be fed on blood from the practicioners neck.
In the Philippines, there is a mythical trickster spirit known as the Alan which is said to use reproductive waste, including menstrual blood, to create human babies, which it then lovingly raises as its own.

Professional Wrestling

During the WWF's Ministry of Darkness storyline in the late 1990s, the sacrifice of Dennis Knight involved The Undertaker slitting his own wrist with a dagger and letting it drip into a goblet, which Knight was forced to drink from. Undertaker then carved his symbol into Knight's chest, proclaiming him Mideon.

Tabletop Games

Amber Diceless Role-Playing, based on Roger Zelazny's The Chronicles of Amber stories.
- A character with Advance Shape Shifting can use their own blood to create creatures which have some of their powers. These creatures are Non Player Characters and not under the creator's control.
- A character with Shape Shifting and Conjuration can create items out of their own blood. A character with Advance Shape Shifting and Conjuration can create items out of other people's blood.
Arkham Horror: The Player Character Agnes Baker, a waitress who learned magic through Past-Life Memories, can choose to spend her Stamina Points to activate spells that are normally Cast from Sanity, which adds extra power to the spell.
Bleak World has a few vampires who can create blood golems, but the only people to get any real blood magic are the Waster witches who use it to restore their youth and the Demon Host who are granted special powers with blood.
Deadlands: Reloaded: The Whateley Blood edge allows you to spill your own blood in order to gain "power points".
- Under the original ruleset, Whateleys got their own brand of Black Magic that was actually accessible to Player Characters. It was fueled by blood drawn from under the characters' skin by otherworldly forces, and some of its examples used the blood as a direct attack or defense.
Dungeons & Dragons
- In earlier editions, a magic user used his own blood as an ingredient in creating a homunculus, possibly inspired by the Sinbad example, though more likely inspired by real-world alchemists' practices, wherein it was believed human blood or human semen was needed to provide the homunculus a spark of live.
- The Cacodemon spell (which summoned a member of one the classes of named, but not unique, demons) had three methods to obtain a service from its target. Relatively moral mages could trap its spirit and exact a service for its freedom, or threaten to inflict torment on it until it agreed, but more evil mages could attempt to appease it with offerings, one of which was a bowl of mammal blood, preferably human.
- The Blood Mage prestige class allows a spellcaster use their own blood to improve their spells. There's a Wizard paragon path along much the same lines in Fourth Edition.
- In the book "Complete Arcane" for 3.5, the Prestige Class of "Blood Magus" is described as "formerly deceased spellcasters who, when returned to life, gain an understanding of their blood's importance..." They can create a homonculous as explained above, but they have many other abilities as well, a particularly frightening one being "Bloodwalk". With Bloodwalk, a Blood Magus can teleport by entering the body of a living creature the same size or bigger, either leaving peacefully or exploding out violently.
- The Maho Tsukai from the Oriental Adventures can, like the 3rd Edition Blood Magus, use his own blood as a replacement for the material components for spells. He can also use someone else's blood, although that takes more time and more blood. Finally, he can use large amounts of blood (enough that it's represented by Constitution damage rather than regular hit point damage) to apply metamagic to his spells without using a higher-level spell slot.
- Forgotten Realms: Many spells are blood-related, like Bladethirst, Bloodstars, Blood Lightning, Beltyn's Burning Blood and elven Blood Dragon, and there are less specific mentions of elven blood magic in novels. Lots of other spells introduced in FR, while not inherently blood-themed, need as a spell component any blood (Revenance, Nulathoe's Ninemen), blood of specific creatures (e.g. red dragon for Daltim's Proof Against Fire, dwarf for Semipermanency) or the caster's blood (Bone Javelin, Elminster's Evasion, Fellblade, Immunity to Undeath, Lich's Touch, Mummy Touch, Phezult's Sleep of Ages, wizardly version of Negative Plane Protection). Components of magical inks, elixirs, etc appearing in Realmslore include blood of various creatures more often than not.
- Ravenloft was created when Strahd von Zarovich murdered his younger brother Sergei, in a blood sacrifice intended to magically restore his youth.
- The 5th Edition spells Summon Lesser Demons and Summon Greater Demon both require a vial of blood from a humanoid creature that was killed within the last 24 hours as a material component. As if the whole part where the spells are about summoning demons wasn't obvious enough about how evil the spells are.
- Critical Role: Tal'Dorei Campaign Setting: The Blood Cleric sub-class is centered around manipulating the forces that control one's body and connects it to the soul. These clerics can channel divinity to control the blood within creatures and force them to make attacks against allies or use samples of the blood of a creature to learn their location or even take control of their senses for a short time.
- La Notte Eterna: The vampire-exclusive ability Blood Bath allows a vampire character to absorb the blood of their enemies and either use it to recover their energy or turn it into a projectile.
Earthdawn
- Blood charms are used to seal Blood Oaths and gain magical benefits. They usually last A Year and a Day.
- Earthdawn Companion supplement. Some high Circle characters can use blood magic to power certain Disciplines (special abilities). These include Resurrect Mount (Cavalryman), Astral Face (Nethermancer), Keen Blade (Swordmaster), Shadowcloak (Thief), Ghost Song (Troubador), Create Orichalcum (Weaponsmith) and Casting Triangle (Wizard).
Exalted:
- All Necromancy spells require a sacrifice of blood as part of the casting. In most cases, this is nothing more than a token sacrifice, and The Black Treatise, the Necromancy sourcebook, notes that necromancers tend to keep bandages handy. For the most powerful rituals, though, more gruesome sacrifices are required; Necromancy is very much Black Magic in the world of Exalted.
- There are also a few Sorcery spells that are not inherently evil and require the use of blood: Blood Lash only works when you are bleeding, and Benediction of Archgenesis, which requires the sorcerer to cut their feet and walk around the area they wish to bless with life.
GURPS: Thaumatology codifies this: you have to spill enough blood to drain 20% of your Hit Points in order to get + 1 to casting. Unfortunately taking damage also makes it harder to cast a spell, so without the High Pain Threshold advantage there's not much point to it.
Iron Kingdoms: Many forms of Black Magic at least dabble with the use of blood as a source of power, but the setting's resident kings are the skorne, a race of hobgoblin-like savage humanoids who are the setting's resident Hordes from the East. Their entire culture is based around the practicing of a form of Blood Magic, which they venerate in lieu of religion. The skorne version is fed as much by pain as it is by blood, though, so its practitioners are also skilled torturers, which is one of the reasons why the skorne are a race of Combat Sadomasochists.
Legend of the Five Rings: Practitioners of maho fuel their spells by spilling blood, often their own. The explanation given is that kansen, malevolent spirits, are attracted to the caster by this act and will then exert their influence over the world in accordance with the mahotsukai's wishes.
Pathfinder: An obscure spell lets a caster use their own blood and Strength in lieu of costly material components, which allows for such oddities as fueling powerful Summoning Rituals and raising the dead with a generous helping of the red stuff rather than shelling out a fortune in gold and rare gems.
Planebreaker: Spellcasters who gain access to Sanguine, the dimension of blood, can use it to become blood wizards, with the power to direct the flow of that life-giving fluid in other creatures.
Rifts:
- Blood sacrifices are common for most kinds of magic because P.P.E. doubles at the time of death. But the actual representatives of this trope are Blood Shamans, who cast grisly spells from their own blood with a bit of Casting from HP.
- One issue of the Rifter features a school of blood magic. The mages are covered in cuts from using their own blood. They can take others' blood, but it has to be fresh, so there's a spell to render a vessel full of blood capable of preserving its contents. Other spells range from a simple, distracting heartbeat sound effect, through to causing someones blood to eat their tissues from inside them, to creating a blood golem.
Savage Worlds: Weird War II: Rune magic is dangerous to use, causing backlashes which can cause the rune mage to die or be permanently brain-damaged. The ability of rune magic to turn people into thralls is useful here, as they can give the mage power (they don't track power points) and even absorb backlashes. This is going to kill the thralls, though due to the Final Solution they have plenty of people to enthrall and no rodents' posteriors to issue, as the magic is evil and only ever used by the Nazis. The process is usually referred to as blood magic and therefore it is more common to call the mages blood mages.
Scion features the Aztec Pantheon as one of its sample pantheons. As a result, Aztec Scions get access to the Itzli Purview, which allows the Scion to gain power through blood sacrifice. These powers range in potency from "sacrifice some of your blood to gain Legend" to "rip out someone's heart and plug it into your own chest, where it catches fire and grants you new-found vigor."
- Likewise, Scions of the Aesir get access to Jotunblut, which allows them to use the blood of the giants to make mortal companions stronger. At the highest levels, it allows mortals to turn into giants themselves.
Shadowrun
- In Shadowrun, Blood Magic is a discipline that utilizes sacrificing sapient victims to boost magic power or grant access to talents a mage would otherwise not have. Because of it's nature, it's heavily associated with the worst sociopaths and monsters metahumanity has to offer, and thus reviled even by criminals and the worst elements of polite society.
- In a world filled with amoral megacorporations, pervasive criminal activity, and the occasional horror story rooted in some truth, unethical and even downright villainous forms and practices of magic are tolerated and even fairly common in some settings, so long as it's used to push for somebody else's goals. Still, Toxic Magic, Bug Magic, and, of course, Blood Magic are the only forms of magic that are universally reviled. While people will tolerate and even encourage negative uses of most other traditions, the utilitarian and beneficial uses of these shunned forms are very limited, and can only really be used to destroy and drive their practitioners insane; and it's a very closed secret at present, but they are also associated with the Horrors.
- That said, there have been a few positive uses of Blood Magic. The 5th edition source book Dark Terrors, it's explained that some uses of blood magic are a matter of scale and intent. Small scale blood magic using non-lethal amounts of blood, either drawn in the normal course of combat or through willing donation, matched with selfless intent to help protect and save others, can be used with less or even no corrupting effects. It was said that when members of the NAN performed the Great Ghost Dance, most of the practitioners danced themselves to death. The completion of the ritual caused a massive global mana spike, the effects of which are still being felt and researched some 70 years later. The immediate effect was to cause a dozen of the largest volcanoes in the North American continent to erupt simultaneously, routing the American and Canadian waging war on the NAN. While it was largely driven by desperation and killed most of its practitioners, it won the NAN the war and saved the friends, families, and communities of those that performed the ritual.
- Supplement Aztlan. Aztlan mages can use Blood Magic: spilling a human's blood to enhance spellcasting and summon Blood Spirits. Extremely evil, restricted to Non Player Characters. How restricted? If any player character starts learning Blood Magic from any source whatsoever, of their own free will, their character sheet is now that of an NPC. It's just that dark. Another reason for the NPC-turn is that Blood Magic is one of the most jealously guarded secrets in the world and Aztlan spares no expense in exterminating outsiders who learn about it with extreme prejudice. We're talking "nuke the block to get the guy who stole our secrets"-guarded.
- Expanded in the supplement "Street Magic". Adepts can benefit from blood magic, with at least one of the new metamagics revolving around cannibalism.
- 5th edition blood magic also provides an alternative to augmentation in the form of blood crystals, which when applied to a severed limb or damaged organ can replicate the effects of cyberware & bioware without essence cost associated with those, thus allowing mages access to those benefits without sacrificing their power - unless the crystal is removed, in which case the essence comes with it.
In Vampire: The Masquerade, all vampires gain their abilities, obviously, from consumed blood. However, a few clans take this one step further by developing a blood-based system of sorcery stronger than the hedge magic any human can learn but weaker than the Sphere Magick of Mages. The most well-known practitioners of blood magic are Clan Tremere, whose original members were Mages in life.
- Vampire: The Requiem carries this on with various forms of Blood Sorcery, the two most predominant being Cruac (a humanity-stifling, ritualistic art practiced by the Circle of the Crone) and Theban Sorcery (a series of "miracles" that require appropriate sacrifice, practiced by the Lancea Sanctum). A third example is the bloodline power of the Gethsemani bloodline, which allows them to make mortals spontaneously suffer stigmata-like wounds; the blood from these wounds has magical effects on a vampire who drinks it.
- Hunter: The Vigil features the Cainite Heresy, remnants of an ancient cult that weren't too happy after being dicked around with by a vampire claiming a direct connection to God. Somehow they got their hands on vampiric blood magic, and created the Rites of Denial, special powers meant to deny vampires their innate advantages.
- Changeling: The Lost has Tokens, magic items that activate with a simple burst of Glamour or with a simple Wyrd check. Either of these can be foregone- and the items can be used by mortals- by paying the "Catch," a "dread cost." Examples? One, a minor thing that empowers your car, requires you to run your car on a pint of your own blood (one point of lethal damage); another one, a more potent one called a Pledge Stone, requires you to rip out your own tongue and burn it (one point of lethal damage and you don't have a tongue).
- And in Mage: The Awakening, blood sacrifice (namely, draining a being, including a human, of its blood until it is dead) can be used to replenish Mana. The use of blood can also correspond to the powers of Mastigos or Thyrsus mages.
- Part of the reason the Garou of Werewolf: The Apocalypse slaughtered the Camazotz was the werebats' use of human blood in magic, which the Garou didn't understand wasn't a corrupt art. Combined with the Camazotz' demonic appearance and status as spies, the Garou sent the werebats into extinction. Which is heavily responsible for the totem Bat falling to corruption of the Wyrm.
- Geist: The Sin-Eaters has the Stygian Key, a source of power based around manipulating the raw essence of death. Few Sin-Eaters obtain it, as you need to drink from several rivers of the Underworld and make a deal with a Kerberos to learn its tricks. But even then, you can only use any of the Manifestations associated with the Key by performing a sacrifice first. There's also the Stigmata Key, which is much more common and allows the Sin-Eater to control blood and ghosts. Some of its Manifestations require a portion of blood in order to function, and it can sometimes be empowered by shedding blood when you don't need to.
Dark Elves in Warhammer use blood magic. Their sorceresses can sacrifice wounds to get more magic dice, and they have large blood cauldros that imbues nearby units with the blessings of their god Khaine (also known as the bloody handed god).
In Warhammer's sister franchise Warhammer 40,000, Chaos often asks you to starts shedding lots of blood — whether it's yours or your enemy's depends on how Tzeentch is feeling that day — for anything more complicated than boiling water, though the most common ritual in any given cult will be summoning daemons.
- And, lest we forget; BLOOD FOR THE BLOOD GOD! SKULLS FOR THE SKULL THRONE! Khorne's followers really go nuts over this sort of stuff, although it's less about fueling magic than it is showing one' s devotion to Khorne and being rewarded with greater strength as a result.
- Appropriately, the Khorne Daemonkin faction has this built into their rules; Khorne units are incapable of using psychic powers or sorcery, so to buff them the Daemonkin were given the Bloodtithe rule. Any unit with Bloodtithe generates a counter for each unit it kills or if it dies, and counters can be accumulated and spent to provide a variety of effects, ranging from buffing your army to summoning a bloodthirster. Because the mechanic doesn't care who dies, so long as someone does, this encourages players to bring tons of small, minimum sized units to get the maximum amount of bloodtithe counters for the amount of models they lose. Khorne truly does not care from whence the blood flows, only that it does.

Theatre

Westeros: An American Musical: Part of Stannis' storyline involves his bastard nephew being used as a Targeted Human Sacrifice by his Court Mage.

Video Games

Avencast: Rise of the Mage: The melee skill tree is called Blood Magic, but it's more likely to reference blood spatter from melee-range physical attacks than dark mysticism.
Bloodborne: The Healing Church's special blood can cure any ailment and has cemented the church's power over the city of Yharnam. Too bad it belongs to/is an Eldritch Abomination and gradually transforms people into horrific beasts.
In Bloodstained: Ritual of the Night, optional boss (and playable character) Bloodless is a vampire that uses many skills based on manipulating blood.
Brütal Legend: An inadvertent version. When Eddie is badly injured due to the carelessness of the idiot band he works for, his blood drips onto his belt buckle and summons Ormagöden, kicking off the events of the game. Given that Succoria was meant to use it to return to her own time after travelling to the future, Eddie could likely only activate the Idol of Ormagöden because Succoria's blood runs in his veins.
Clive Barker's Jericho:
- Wilhelmina "Billie" Church is a powerful blood mage. Her blood magic and abilities play a very important part in the game's story, and her spells can bind enemies and set them on fire.
- The Sumerian demons Inanna and Ninlil also rely on blood magic (referred to as sanguimancy in-game). While Inanna uses the blood of Innocent people bound to torture wheels, Ninlil has herself locked within an Iron Maiden to spill as much of her own blood as possible.
Devil May Cry:
- When you kill monsters you collect their blood (which conveniently crystallized into red orbs in contact with air) to upgrade your magic powers. Justified in that there is a bounty system in placed by some nebulous God of Time.
- Some in-game puzzles or secret passageways require you to redirect fountains of blood to a given object before you can proceed.
- In Devil May Cry 3: Dante's Awakening, Arkham used the blood of Dante, Vergil, and Lady to open up the portal to the demon world. He needs this because the portal was sealed by Sparda (Dante and Vergil's father) using his own blood and the blood of a mortal priestess, Lady's ancestor.
- In Devil May Cry 5, the Qliphoth tree's roots absorb human blood. When enough blood is absorbed, the tree then produces a fruit that grants massive power to any demon that eats it. Mundus became the ruler of the demon world by eating a Qliphoth fruit in the past, according to Trish. Urizen's goal is to do the same. An in-game document file also states human blood as the source of demonic power.
Diablo III:
- In Act V of Diablo III: Reaper of Souls, which has you going through the Blood Marsh near Westmarch, you learn that Adria has started using blood magic, creating blood golems and maddening the boggits, bogans and other monsters of the marsh to try to slow you down.
- Act III of vanilla Diablo III has Adria borrow soldiers killed during the battle of Bastion's Keep to etch a ritual circle with their blood — one which strongly resembles the circles used by the Coven. The circle she uses is to stabilize the Black Soulstone briefly, a window she uses to slam it into her daughter Leah, infusing her with all seven Evils with Diablo in charge.
Disgaea 5: Alliance of Vengeance has Majorita, one of Void Dark's generals. Though called a Necromancer, it turns out her Overload Skill Broken Faith Magia is actually this, letting her control flesh via injecting a tiny bit of her own blood into a target. Powerful as this skill is, letting her revive downed troops to turn them into more useful zombies, it turns out that targets with strong enough wills can resist the control, even to the point of disobeying her commands, and it can be dispelled with angelic magic (Thanks, Christo!). Later on, it turns out Void Dark only kept Majorita around due to this skill, and eventually uses his own Overload, Brigante Eclipse to take it from her and then immediately use it against her.
Diluvian Ultra: Your blood is used for activating certain pieces of technology, probably because you're an immortal undead Warrior Prince. You purposely cutting your hand on the blood-sword to extend it's blade, and when reaching closed portals sealed by Waystones you then perform some Palm Bloodletting and splashes your blood into their core to activate them.
Divinity: Original Sin II:
- Several Necromancer skills create or take effect through blood surfaces, such as a Rain of Blood that inflicts massive Non-Elemental damage and status ailments, ghostly hands that do the same to any enemy standing in blood, and a spell that heals the target by absorbing nearby blood.
- A demon Loan Shark takes a vial of the debtor's blood as collateral — cross her and she uses Sympathetic Magic to splatter you across the floor. You can steal the blood vials to deprive her of her leverage.
Dominions: Spells from most schools of magic are cast using "gems" which are basically elemental forces (fire, water, etc...) concentrated into portable form, and the casting prices of spells are listed in these gems. Instead of gems, however, one school of magic lists spell prices in blood. These prices are listed in increments of one blood slave, each of which must be drained completely empty, with high-level spell costs running into the hundreds. Blood magic is conspicuous in battle, where mages or priests are surrounded by a white-robed flock they systematically stab, especially if the mages start losing and set the slaves to charge into the spears of the enemies while they themselves flee. Dominions is not a happy series.
Dragon Age:
- Blood Mages. Their magic allows them to Cast from Hit Points, drain the life energy of others to fuel their magic, control minds, boil others' blood in their veins, and sometimes even command demons. Despite this, they're not always evil, but most are, and even the good ones tend to be treated as if they are, since the most common method of learning it is through a pact with a demon.
  - The player themselves can become a blood mage in Origins and 2, although Origins players have to unlock it^note through — you guessed it — a deal with a demon during the "Arl of Redcliffe" quest. Oddly enough, nobody in either of your parties ever comments on your blood magic use, even when Merrill (an open blood mage) gets into arguments with the rest of the crew. Blood magic was technically^note dropped as a specialization in Inquisition and Hawke, who could be a blood mage themselves, is now very anti-blood magic (although given what's happened, maybe that's not that surprising).
  - The state religion of the Chantry demands that all persons with magical abilities have to permanently join the Circle of Magi and be confined to their towers where they are constantly monitored by templars who are to slay them at the first sign that demons have possessed their bodies. Every mage who tries to escape from the Circle of Magi or refuses to join is treated as being potentially possessed and killed. Since blood magic is not officially sanctioned by the Chantry, blood mages share the same fate as all other apostates. Ironically, the Chantry itself uses phylacteries, enchanted containers filled with the blood of Circle Mages, to hunt down any who try to escape. Destroying their phylactery is the only way a mage can ensure their freedom.
- Grey Wardens gain their powers by drinking darkspawn blood mixed with lyrium. The cost to this is that the Darkspawn Taint eventually will overtake every Grey Warden, turning them into a Darkspawn themselves. They avoid this happening by suicidally venturing into the Deep Roads and trying to kill as many Darkspawn there as they can when they feel the taint has gotten too strong.
  - In the "Soldier's Peak" DLC, the mage responsible for it being haunted by demons and undead has been experimenting to unlock the power of the Wardens' Tainted blood, including a lot of blood magic and human sacrifice. This gives Wardens who drink his concoction additional powers, whether it's bleeding on their swords for extra damage or spraying blood like a fire hose.
  - Conversely, in Dragon Age: Origins – Awakening, it's revealed that the sapient darkspawn that have been showing up originated from a Rogue Drone called the Architect who found out that he could use a mixture containing Grey Warden blood to turn other darkspawn into Rogue Drones as well.
- Another example of this are Reavers, warriors who ritually drink dragon blood to gain the ability to drain the lifeforce of others to replenish their own, among other things. Oddly enough, despite skirting very close into the same territory, becoming a Reaver is not frowned upon by the Chantry. Strangely, some members of the qunari race are known to develop Reaver abilities purely through training, which has certain implications for their history.
- In Dragon Age II, the Legacy DLC reveals that twenty years previously, Malcolm Hawke was forced by the Grey Wardens into using blood magic to reinforce the seals of an ancient Grey Warden prison. An unintended side-effect of this was that only those of Malcolm's bloodline are able to break through the prison's defenses and free Corypheus, causing Hawke and their sibling to be targeted by the Carta.
- Dragon Age: Inquisition reveals that Red Lyrium is lyrium Tainted by the Blight, which would only be possible if lyrium was alive. In other words, using lyrium to power magic is simply another form of blood magic. The DLC mission The Descent confirms this: lyrium is actually the "blood" of enormous subterranean creatures called Titans.
The source of the cultists' powers in DUSK, granted to them by Nyarlathotep.
Elden Ring:
- Blood Oath Incantations are a school of spells that revolve around summoning massive quantities of red and black blood from a portal and can be used a variety of purposes: ranging from setting it aflame to brainwashing flies with the scent to make them fight for you. Happening upon a certain Brutal Bonus Level reveals that blood magic was first invented by the Mohg, Lord of Blood (a member of the Lands Between's Demigod royalty abused for having been born deformed) and is in truth fuelled by the Formless Mother, a sadomasochistic Outer God who offered the young Omen the chance to take his mother's crown in exchange for spreading the use of her evil magics.
- There are two blood-based sorceries that are not related to the above incantations, drawing their power from red glintstone and manifesting as The Hedge of Thorns. Unlike most sorceries, they require Faith and not Intelligence, essentially making them incantations in all but name.
- Dragon Communion is the act of partaking in the blood of dragons (via eating their hearts) to gain their power. Abusing this by eating too many hearts turns people into Magma Wyrms, grotesque parodies of true dragons who cannot fly and can only crawl on their bellies. Thanks to Gameplay and Story Segregation, a player character doesn't have to worry about any changes except their eyes turning yellow and reptilian. The Dragon Communion Seal that boosts Dragon Communion incantations is even made of drake blood. The item lore for the seal notes that "incantation" isn't really the right term for these spells since they are too primal in nature. Like the Blood Oath incantations mentioned above, these "incantations" also have Arcane stat requirements.
The Elder Scrolls V: Skyrim:
- The only way to open the old Blades headquarters in Skyrim is with the blood of a dragonborn.
- In the Dawnguard DLC, the lock sealing away Serana requires blood and a small puzzle to open it.
  - The same DLC adds spells actually called "Blood Magic" as a part of the special Vampire Lord skill tree.
Endless Legend's Ardent Mages discovered that intense suffering allowed them to control Dust to perform their magic. Ardent Mages practice ritual scarification, and their cities have floating jail-cells with trapped citizens to generate magic. One of their unique buildings, the Sacrificial Amplifier, has hundreds of living Mages strapped to a massive pillar which is burning hot; the description then notes that the magic generated is well worth it despite the cost of screams and stench of cooked flesh and shit.
Fate/stay night: This is one of the ways a Servant is summoned. You take some chickens, put them to sleep, kill them, draw out their blood and make a magic circle. Then, you can either use a catalyst for a specific hero or just the general term of inducing madness in order to get a Berserker. Rider and Caster in Fate/Zero were also summoned in this manner, and it's more noted upon there as well.
Final Fantasy: The Dark Knight class has the ability to sacrifice health to either empower or fuel their attacks.
Taken to the extreme in Final Fantasy Tactics, in which human sacrifice is used on a titanic scale by Lucavi, inciting a war with hundreds of thousands of casualties to spill enough blood to raise the Big Bad Altima.
Almost literally in Final Fantasy Tactics A2, where the skill "Blood Price" lets you use HP to pay for magick instead of MP. The catch? The HP cost is double the normal MP cost, and you can't use your MP at all with this skill equipped. However, the simple convenience provided by it more than outweighs the drawbacks. Not to mention that you still get HP back if you use it for healing spells.
In God of War II, at the Temple of the Fates, Kratos is required to capture a translator to read the incantation needed to open his path. Said incantation ends with the reader offering his blood as a sacrifice. Cue Oh, Crap! just before Kratos bashes the guy's head in against the altar, his blood draining into a pattern etched onto the floor.
In God of War Ragnarök, the Lady of the Forge asks for the blood of a god (in this case, Kratos) to complete the Draupnir Spear.
In Guild Wars a Necromancer's blood magic skills often have you sacrificing health to achieve an effect. The same class also uses Death magic, which exploits your dead opponent's corpses (and therefore blood) for similar effect, and their innate Soul Reaping ability, which heals you upon an enemy's death. Blood magic also has you drain health.
In Hades, Zagreus uses bloodstones — crystals formed from his own blood — as catalysts for his magic Casts.
Hatoful Boyfriend: In the second game, a Mad Scientist starts drawing the blood of Anghel Higure, who has bizarre hallucinogenic powers tied to his fantasies, and using it so he can power a giant lazer with kidnapped otaku.
While technically no actual blood is involved, one of the main mechanics of Inscryption is sacrificing cards on the field for blood in order to play better cards (spending said blood in the process). It turns out this is only one of four card types, but since it's the one that your opponent Leshy specializes in, it's what you start with. After your first run ends, you also start unlocking bone cards which are a sort of indirect form of Blood Magic (your cards must die to gain currency used to summon other cards). The other two card types that don't unlock until the second half aren't this at all.
Jade Empire: The defenses of Dierge were broken when the sacred fountains were polluted with human blood. Useful in the nastiest way possible if you take the Closed Fist option.
League of Legends: Taken to the extreme again by Vladimir the Crimson Reaper, a "hemomancer". Not only are all his abilities blood-related (including draining the blood out of his opponents and into him and briefly turning into a near-invulnerable pool of blood) but he fights with an orb of blood which hovers in his hands that he shoots at his opponents. His skins also seem to fancy him as the closest equivalent the game has to a vampire.
- Blood magic was confirmed by later lore to be the magic of the darkin, as best exemplified by Aatrox, whose entire body is built from blood magic being used to bind corpses together into a Big Red Devil.
- Legends of Runeterra adds the Crimson cards — Crimson Aristocrat, Crimson Awakener, Crimson Disciple and Crimson Curator — who are basically punk kids who view Vladimir as their idol and practice blood magic, albeit to a lesser degree than Vladimir. They even synergise pretty well, leading to a few different deck outlines from Noxus that use cards that inflict damage to allies — the core mechanic that represents blood magic, at least most of the time — to either build up to a Glass Cannon approach (say, combining the Crimson cards and Vladimir with Freljordian cards that get stronger when they take damage) or to just shrug it off (say, going for Targon and combining Vladimir with Soraka's healing subtheme).
Messiah: Satan feeds on human blood, which is what he needs to "physically exist in the Earthly realm"; he also seemingly derives his power from it. Scientists' logs in the final level suggest that he managed to break free from his imprisonment in the research facility when they accidentally gave him too much blood to drink.
Minecraft: One mod has Blood Magic, Blood Arsenal, Blood Baubles and Sanguimancy, which all use blood — either drained from the player or from enemy mobs — to some degree. Its liquid form is called Life Essence, but it's bright, blood red in color so it's rather obvious what it is.
Mortal Kombat 9: Shao Kahn created Skarlet out of blood collected from various battlefields. This was later retconned and Skarlet was a normal outworlder who learned blood magic from Shao Khan and became one of his most fearsome assassins.
NieR: Grimoire Weiss absorbs the blood of fallen enemies to create magical constructs for his partner to attack with.
In Ōkamiden, the Big Bad Akuro must bathe his vessel in blood to become perfect. Specifically, Orochi's blood. Or, maybe he has to bathe himself. The game can't agree with itself on this point.
In Planescape: Torment, crystallized blood droplets are used for healing potions.
In Sable's Grimoire: A Dragon's Treasure, Sable is forced to wear a magical amulet containing Nidhogg's blood. This constant exposure to a dragon's blood gradually transforms Sable into something akin to a dragon, with the process accelerating once the amulet starts injecting that blood directly into his veins.
The Secret World features this as one of the three magical disciplines players can take on, and generally revolves around healing and damage (with life drain). Also, while with all skill sets you have to use weaker skills to build up "resource" charges which are spent on more powerful skills, you can still cast powerful blood magic skills without sufficient charges — you just sacrifice health instead.
- In the rework to Ssecret World Legends, Blood Magic uses a system of Martyrdom and Corruption: using the healing and defensive spells increases Martyrdom while using damage-dealing spells increases Corruption. If one gets too high, the player starts taking damage and has reduced healing, so balancing offense and defense is important if Blood Magic is your specialty.
In Soul Sacrifice, you are given an option to Cast from Hit Points for either short bursts on a wide area or continuous slashing. The only two who use this are the player and, most fittingly, Aegrus.
Space Station 13: The aptly-named Blood Cult of Nar'Sie on /tg/station and its derivative servers employ this. The exact abilities vary depending on the codebase, but always revolve around sacrificing or converting crew-members, and painting bloody runes onto the ground to cast rituals, such as conversion, or summoning Nar'Sie, the Geometer of Blood, to the station and feeding all the crew onboard to them. Some servers allow the cultists to paint bloody talismans or carve runes onto their own bodies, allowing them to use portable spells, ranging from stunning potential conversion targets to turning their own blood and the blood of others into weaponry.
This Starry Midnight We Make: Yi Xinghua, a resturanteur, in the completion cutscene for the first of her questline slightly accuses the protagonist of this to improve the resturant:
So you two really did do something, huh?
What kind of crazy blood magic did you do, I wonder?
Touhou Project: According to Marisa, Remilia Scarlet utilises this for a few spellcards. Blood is amazing!
Vampire: The Masquerade - Bloodlines: The Tremere vampire clan's unique Discipline, Thaumaturgy, manipulates blood. Powers include long-range Vampiric Draining via blood projectiles, inflicting a status effect while the target vomits blood, forming armour out of blood, and making people explode in superheated gore.
In Vanguard Bandits, the monstrous Zulwarn ATAC needs Blood in order to run.
Warcraft:
- Warcraft II: Tides of Darkness: Death Knights, after being researched at the Temple of the Damned gain the spell Unholy Armor, which adds a nearly impenetrable suit of armor at the cost of half of the target's HP.
- Warcraft III: Reign of Chaos introduces Blood Mages, but despite the name they don't practice any of this; most of their spells are fire-based. Lampshaded by one you meet in the Blasted Lands, who says Blood Mages "eat normal food like normal people."
- World of Warcraft:
  - According to the background, a warlock's life tap ability (convert health to mana) works exactly like this (they sacrifice their own blood to gain mana), using it to summon most of their demonic pets, empowering their weapons or, curiously enough, a number of beneficial effects like summoning party members or Healthstones which can be consumed like a potion.
  - The Mogu, resident Lawful Evil villains of Pandaria, utilize a mysterious red substance called Anima to animate their Blood Golems, but it does not seem to be normal blood. It's not until late in the Isle of Thunder storyline that you find out what it is: the blood of Ra-den, the divine guardian of their species whose blood and secrets they stole and used to build their empire.
Zelda II: The Adventure of Link: According to the manual, the monsters want to kill Link to use his blood to revive Ganon. They apparently succeed if you get a Game Over...

Webcomics

A BETTER PLACE: The being that granted Hannah and Theo their powers was summoned by a combination of Theo's blood from thornbush scrapes and Hannah frying an anthill:
- As said in the author commentary for Forgotten Shrine:
And by blood, and by fire, and by sacrifice, shall I be called
- In One Wish:
"By Blood, Fire and Sacrifice"
"I am brought forth!"
Biscuit begins with a character opening an envelope sealed by blood magic.
The Boy Who Fell features blood demons who can work powerful blood magic.
- The tiny cinnamon roll Saffron nearly beats one of the strongest fighters in the comic by stabbing himself and turning his own blood into attack snakes. To be fair, Sorian's full output was sealed by a curse. He also manages to solo-kill a sea creature known for preying on fully grown adult demons.
- The last human alive before human abduction became outlawed, apparently was killed by a blood demon, since even his strength could not overcome blood magic.
Demonseed Redux!: Rhoda scratches Chico's face and then does a magical ritual with his blood, turning him into part-incubus remotely.
In Drowtales, blood sorcery is a branch of mana manipulation.
- Syphile, Ariel's abusive caretaker, has an affinity for blood magic and uses it against Ariel at few times since she's especially vulnerable to it due to her own mana affinity.
- Chrys'tel is able to use her blood as a projectile and also essentially make grenades using vials of it.
- Later on we get a dark take on the idea when a human king begins a campaign of kidnapping and brutally killing elves so he can bathe in their blood, hoping to gain immortality.
- Yuh'le, one of Snadhya'rune's proteges, has a particular potent combination of empathy and this that allows her to explode people from a distance and make bleed from every orifice.
In Familiar Ground, how they know that Toad's wizard is evil.
In Heart Core, there are a few characters who has this ability. Royce has shown to have the ability to controll spilled blood (his own and others) in order to use them as strong tentacles that can grasp and crush bones of weaker creatures. Then there are the Salamander Demons, Carval and Volaster Jarvoc being some of them, who can use their black, flamable blood in order to creature very powerful fire-bombs in an isntant. That is, when they don't opt to turning themsleves into living nukes.
In Looking for Group, when Cale's swords are exposed to blood, they reveal a map to Kethenecia.
Qarr in The Order of the Stick mentions using virgin's blood as a spell reagent.
Timmy from Parallel Dementia can use blood magic.
In Penny Arcade's Eyrewood Adventures comics, a person in dire need can summon the Thornwatch by tying briars in a particular way around a birch tree. No, you can't wear gloves: "With bow and blood, the spell is done."
Rebirth: It turns out that Noah can manipulate his own blood into a weapon.
The Erlkönig in Roommates used his own blood to seal his son's magic and memories (symbolically his left eye). What power the guy has that a the blood of a blood related fae noble was needed is anyone's guess (maybe the Erlkönig is just a show off).
Rachael from Silver Bullet Nights is a mistress of blood and magic. Using blood, she can summon up demons, enslave other vampires and make a delicious cocktail for undead clients.
Sleepless Domain: In a pinch, Undine's water powers can be used to control blood — albeit to a very limited extent, as blood isn't pure water. It's not good enough for practical applications, but it was good enough for her to cling to life for a few precious minutes, letting Tessa catch up with her and save her.
Sluggy Freelance:
- The blood of the innocent awakes a powerful magic spirit in Torg's sword.
- Only Gwynn can use the Book of E-Ville to cast spells because her name has appeared on the inside cover written in blood. Right above instructions to, if lost, drop in any mailbox to return it to the rightful owner.
Stand Still, Stay Silent: When Reynir gives out his attempts at protection runes in Chapter 11, Sigrun suggests that they may work better if drawn in blood. Reynir is grossed out by the idea. It may also not be a good idea to try in his case: he is not The Immune to The Plague, there was a small scare when he barely avoided getting scratched by a Plague Zombie and he has to wear a breathing mask outside half the time as a precaution for the fact that The Plague is partially airborne.
In Supernormal Step, Jules and Van practice blood magic. However, Jules made Van swear not to use blood magic without his guidance. Van later uses blood magic to contain a magic riot almost single-handed.
In Tamuran, the princes' blood is needed for a working.
In Tower of God, King Jahad transfers power to the Princesses of Jahad, his adopted daughters, by his blood.
Treneth in Visseria is shown preparing his magic-payloaded arrows by writing scrolls in his blood and tucking them inside.
In The Greenhouse, the demon 'Red' was initially sealed into her mirror with a blood curse, which transferred to Mica when she shattered it and cut herself on the glass. Now only a highly skilled blood mage could separate them safely. The first such mage she's sent to can't actually use it at all, and was just going to con her. But the next one found is a master of the craft... and also her neighbor's grandmother. Liv considers just learning it herself, but as Riley points out, it would take years to become skilled enough for the 'surgery' that Mica requires.
The Embodiment of Sins: The Crimson Knights seem to have gotten their name from this: Lady Yuri breaks a vial of alchemically altered blood over her sword while chanting in Latin, which causes it to burst into flames. A panel at the end of the chapter explains that this enables humans to cut through goblins' tough hide and destroys them from the inside.

Web Original

In The Gamer's Alliance, blood magic is one of the magic schools which has a stigma on it when it was abused in the past. Because of this, very few mages are skilled in it, some notable exceptions being the Alentian councillor Harrad U'niviel and the wandering sage Dieter von Waldheim.
In the Breeniverse series lonelygirl15 and KateModern, infusions of Trait Positive blood can extend the human lifespan considerably. In LG15: the resistance, Maggie's blood grants total immortality.
SCP Foundation, SCP-2791 ("Fauste Bank plc"). The SCP-2791 creatures use blood magic contracts as part of their procedures to set up their convoluted Deal with the Devil schemes.
In Tall Tales, Jackie infrequently uses her own blood to power spells when she lacks proper components, and the Brood of Nachash utilizes blood and human sacrifice in their rites.
Void Domain: Eva is adept in blood magic, which she uses to devastating effect in combat, as well as to create powerful defensive wards and in complex Rituals. In-universe, blood magic has a very unsavory reputation as The Dark Arts; although it has many neutral applications and can even accomplish unique feats of healing, many of its most powerful spells are fueled by transmuted human hearts.
Fey has used this in the Whateley Universe against a dark mage who was trying to enslave her.

Western Animation

In American Dragon: Jake Long a drop of Jake's blood is used to restore the Dark Dragon's full strength.
In Avatar: The Last Airbender and The Legend of Korra, bloodbending is a forbidden subset of waterbending that allows talented waterbenders to bend the blood of a person, controlling them like puppets.
Onyx Equinox, being based on Mesoamerican mythology, places a strong emphasis on this. The gods need blood for survival and Izel found a dagger that transforms into a powerful weapon via drinking blood. Also, the only way to summon Yaotl is for Izel to shed blood on the earth.

Real Life

A number of Islamic Scholars accused Saddam Hussein of dabbling in this trope when he commissioned his infamous Blood Qur'an. That said, even those who didn't believe in magic were disgusted of the act. Saddam's own rationale for commissioning the Blood Qur'an was as a means to thank Allah for protecting his regime over the decades which really might count as an attempt at blood magic, if you are feeling generous.
Some women slip their menstruation blood into the food of their objects of affection out of some folk magic culture's belief that this will bind the victim into staying in a relationship with the perpetrator forever.

Examples:

Video Example(s):

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