Sidera Maris (Multiverse)

The Sidera Maris were automatons^[1] the Mapmakers left behind on the Earths they ravaged to wait for a blue incursion between universes. When one of these dead Earths made contact with a still-living one, the Sidera Maris held the incursion point until a piece of their dead world crashlanded into the new one, marking it for their masters.

The Illuminati got an up close and personal look at what the Sidera Maris could do when an incursion between their Earth and the lifeless Earth-13761 occurred. The incursion stopped when the Illuminati set off a bomb which destroyed the other Earth.^[2]

Through the use of the Bridge, Mister Fantastic witnessed the domination of Earth-2319 by the Sidera Maris and Mapmakers over that world's mutant race and the Illuminati at the floating city of Tian.^[1]

When a blue incursion occured on Earth-4290001, the Sidera Maris were defeated by the Great Society and the anchor Earth was destroyed, though the Sidera Maris managed to summon four Mapmakers. The Great Society defeated them as well.^[3]

In a later blue incursion, the Builders ambushed the Mapmakers and Sidera Maris with an army of Alephs and Ex Nihilii.^[4]

Markers to map worlds and summon the Mapmakers.^[2][1][3]

Blue incurisons.^[2][1][3]