They descend from the skies. They have a hunger for human flesh. They are everywhere. They are parasites, alien creatures who must invade - and take control of - a human host to survive. And once they have infected their victims, they can assume any deadly form they choose: monsters with giant teeth, winged demons, creatures with blades for hands. But most have chosen to conceal their lethal purpose behind ordinary human faces. So no one knows their secret - except an ordinary high school student. Shin is battling for control of his own body against an alien parasite, but can he find a way to warn humanity of the horrors to come?

    But his quiet existence is shattered when the Grey Wolves of Iga, a powerful ninja clan, attempt to kidnap him in broad daylight. Only then does Miharu discover that the ultimate power of the hidden ninja realm — a power that can do both great good and great harm — is sealed within his body. As battles erupt among rival ninja clans seeking to control him, Miharu must overcome his apathy and learn the ways of the ninja if he wants any shot at survival!

    While parents mourn and authorities investigate, the students and teachers find themselves somewhere far away...somewhere cold and dark... a lifeless, nightmarish wasteland in which their school stands like a lone fortress. As panic turns to terror, as the rules start to fall apart, a sixth-grade boy named Sho and his friends must fight to survive in an alien world...

    As he progresses through the game with old friends and new, he meets a mysterious girl...

    He thinks of himself as a bystander and will always write down everything he sees in a cell phone diary. Tormented by solitude, Yukiteru began to imagine things like a friend called Deus Ex Machina who is apparently the Lord of Time & Space. Seeing Yukiteru's miserable state, Deus gives him a new ability. His diary will now record events that will happen in the near future. Yukiteru is then forced to participate in a game which the winner will become Deus's successor.

    Kleio Academy is a very exclusive school. To enroll, a student must be the clone of a famous historical figure. Wolfgang Mozart, Queen Elizabeth, Sigmund Freud, Marie Curie, Adolf Hitler—with such a combustible student body, it's only a matter of time before the campus explodes!SHIRO KAMIYA (2XXX– )The only non-clone at St. Kleio Academy, a school dedicated to the clones of great historical personages. Shiro's father is a professor at the academy. Why is a regular kid taking classes at the school? Nobody seems to know for sure.