In`youchuu The Animation(2006)

Based on the erotic game by Tinker Bell.

In'youchuu The Animation is a supernatural action series following three students who find themselves trapped in their school after dark. While battling otherworldly enemies late at night, they're suddenly ambushed and unable to escape. The series blends horror and action as the characters struggle against the supernatural forces that have cornered them. Based on the adult game by Tinker Bell, the anime adapts the source material's dark atmosphere and intense encounters.