Ao Oni (青鬼, lit. 'Blue Demon') is a freeware role-playing horror video game. The game features puzzle and RPG elements, and revolves around a boy named Hiroshi, who is trapped with his friends in a haunted mansion, and is stalked by a monster. The player assumes the role of 'Hiroshi', a young teenager who enters a haunted mansion with his friends, Takuro, Takeshi, and Mika (Along with Kazuya and Ryota in the original). Shortly after entering the mansion, the doors lock behind them. Hiroshi doubts that the mansion is haunted, but soon finds himself being pursued by an enigmatic blue Oni. Hiroshi must now find a way to save as many of his friends as possible and escape the mansion alive.