Trivia

Natsumi was set to reappear as Endou Mamoru's wife, and would have played a major role in the story arch involving Endou's supposed death. However due to the negative backlash that Endou's romantic relationship with Natsumi in GO garnered, this aspect was removed. The video game version of Chrono Stone addresses this via a side mission that explains that the effects of time travel has resulted in Endou temporarily having multiple wives, and Tenma (the player) must determine which wife will stay as Endou's permanent one. In the anime, however, Natsumi's fate is left entirely undetermined, as she is not even mentioned.