Torikago Gakkyuu

Mikage has just arrived at his a new school. But why can't he remember anything about his life before the moment he set foot in the school grounds? His classmates, while appearing ordinary enough, all possess strange habits and weird personalities.

Soon after, our bewildered protagonist is summoned by one of his teachers, who claims that Mikage has the power to influence a 'parallel universe' - and that his interactions with his classmates will decide the fates of the inhabitants of that universe. Though initially fascinated, he soon finds out that these 'powers' do not bode well for his new school life…

Note: published in GFantasy, a shounen magazine.