Ao Oni

Prolouge: The Mansion

Ao Oni begins with four friends: Mika, Hiroshi, Takuro, and Takeshi. They visit a strange mansion they heard about. The player controls Hiroshi whom, after hearing a plate shatter, decides to investigate. After picking up a plate shard, he heads back to the entry way to find his friends missing and the front door locked.

Hiroshi finds Takeshi hiding upstairs in a closet, unable to speak. Soon after, he encounters the monster in the library and is chased. Hiroshi runs into Takuro while searching the upstairs and Takuro agrees to search the first floor. As Hiroshi is about to enter the basement , a scream is heard upstairs and Hiroshi finds that Mika has been killed by the monster. Soon after, in the basement, he finds Mika transforming into the monster herself . From there, he enters the Annex and finds Takeshi . Takeshi is heavily disturbed by the events, and blames himself for them. Soon after, he hangs himself and transforms into the monster as well shortly afterwards.

Annex Basement

The annex leads into the annex basement, which is the fourth area of the game. At one point, Hiroshi will be chased by two of his friends morphed into Character Onis , showing that there is more than one monster - something the other versions have left unclear. He finds Takuro, who has broken his ankle, hiding in a closet. Takuro gives him the vinegar. Very soon after, he finds the rope ladder exit to the outside. He returns to get Takuro, but when they attempt to escape, the Oni is waiting. As he flees, Takuro trips and is supposedly killed by the monster.

The Old Building

Hiroshi soon finds his way into the Old Building, the fifth and final area of the game. Hiroshi here finds the Oni Room - an empty, caged room full of all sorts of other blue demons. Before he can investigate further, one of the monsters opens the cage door and they all escape. None of the monsters are ever seen again. Hiroshi finds Takuro, who then joins the party. Not long after, Takuro will suddenly turn into an oni and chase Hiroshi, revealing that the Character Onis have the ability to morph back and forth at will. Hiroshi is able to escape from the Old Building, and flees back to town. He remarks in the epilogue that he never saw any of his friends or the monsters again.