"That One Japanese Exchange Student"
We don't actually know WHO "that one Japanese exchange student" is, but we do know that they are extremely powerful...
Where are they from?
Even Pika is unsure exactly who this might be, and there are literally thousands of possibilities. She suggests two:
Haruhi Suzumiya, the main character (although not protagonist) of the anime series of the same name, who has the unconscious ability to change, reshape or destroy reality as she desires...
or Tetsuo Shima from the celebrated 1988 anime Akira, whose psychic abilities evolve so rapidly he destroys neo-tokyo before evolving.... you know what? just watch it. it's amazing.
But for my money, if you're going to have a supremely destructive Japanese import, you don't mess with the original. Does it make any sense for legendary movie-monster Godzilla to be an exchange student in the building-verse? Probably not. Shut up.
Comic Appearances
GND 173 - after an explosion Sarah, Christine & Liz find Leia & Lydia. they wonder if it could be Adam Young & "that one Japanese exchange student.", or Ramona Flowers & Scott Pilgrim. James & Eponine explain that it's the Evil League of Evil, and that Javert is off-campus with Jean Valjean. Lydia talks down Beetlejuice, while Leia complains that Danny still has dragons & Luna has her wand, and wonders if she can use Ewoks.