Yuuma is the mascot of a theme park and starts to love in the dorms where he gets a new roommate, Kazuha, a janitor with an odd personality. They seemed to have a good beginning but later Kazuha's personality change radically and Yuuma finds himself being pushed down and being forced, saying that he's Rei and greeting Yuuma as old acquaintances. Later, some other sudden changes in his personality and behaviour show and Yuuma is now sure, Kazuha/Rei are not the only ones there.
Adam no Rokkotsu