The Ao Oni is the enigmatic primary antagonist of Ao Oni. He is a creature who lives in the abandoned mansion on the outskirts of town. Not much is known about the Oni, but he comes from a world with many creatures that resemble it.
The Oni is a lavender humanoid creature with a large distorted head that vaguely resembles a human. He sports large, glassy eyes, a bent nose, and a tiny, featureless body. He always has the same bemused expression on his face. the back on his head are black suggesting that he either has black hair or rather just the dim lighting.
In version 5.2, the Oni takes a more threatening appearance in Takeshi's nightmare, should you get the best ending. In the nightmare, the Oni's eyes are more similar in appearance and is baring its teeth. With its mouth open, the player can see that the Oni has sharp teeth as well as tusks.
In the live-action movie adaptation however, there are some noticable changes on Oni's appearance:
- While his head remain large and distorted, his face are less distored with green eyes with crude slits, and having feral expression instead of remain in bemused over course of movie.
- Oni in the movie has sharp teeth like in version 5.2, but lacks tusks and smaller but more numerous.
- Oni's right hand are larger in the movie.
- In the movie, Oni was indeed bald and lacks hair. His skin also crude in appearance.
Oni was shown to remain emotionless in spite of followed by murderous instinct to kill anyone who entered his mansion. He also shown to have considerable intelligence, as he able to hide from within closets.
In the movie, he was given more personality while retaining his intelligence and murderous instinct. Here, he displayed sadistic, ferocious, and aggressive tendencies, as he enjoy moments of his victim's fear as he attacking and intimidating his prey by mimicking their friends' voices.
It is known to feed upon people and transform. Specifically in versions 6.22 and 6.23, it has been shown that after the Oni kills, the victim becomes an Oni themself, turning against the main protagonist, in this case, Hiroshi. These transformed Onis also seem to be able to take the form of the original character. This is shown when "Takuro" asked Hiroshi if he could go with him, when Hiroshi goes to put the blue piece on the paper, Takuro turns into a Character Oni and chases Hiroshi. In their true forms, Oni retains the hairstyle of their former disguise.
In the movie, ability to turning victims into another Oni was replaced with ability to mimic their prey's voice and even abiliy to speak Japanese fluently. This likely because Oni in the movie feats upon victims' body outright and often, if not always, only left their mutilated corpse.
Ao is a Japanese word meaning "blue" and Oni meaning "demon" so its name literally translates to "Blue Demon". They are popular characters in Japanese art, literature and theatre. Depictions of oni vary widely but usually portray them as hideous, gigantic ogre-like creatures with sharp claws, wild hair, and two long horns growing from their heads. They are humanoid for the most part, but occasionally, they are shown with unnatural features such as odd numbers of eyes or extra fingers and toes. Their skin may be any number of colors, but red and blue are particularly common. They are often depicted wearing tiger-skin loincloths and carrying iron clubs, called kanabō (金棒?). This image leads to the expression "oni with an iron club" (oni-ni-kanabō (鬼に金棒?)), that is, to be invincible or undefeatable. It can also be used in the sense of "strong beyond strong," or having one's natural quality enhanced or supplemented by the use of some tools.
- Although Ao Oni means "Blue Ogre", many people refer to it as "Blue Demon" or "Blue Troll".
- In-game, even though it is named "The Blue Ogre/Demon", it's coloring is actually closer to a lavender hue. It is unknown whether it was a sprite error or intentional. It is possible that "Ao / Blue" could simply be a proper name, and not a description of his actual color.
- According to the ending of the game, the Oni sees through a form of thermal-based vision, similar to the titular alien from the movie "Predator". However, he was given normal vision in the movie.
- Oni in movie often nearly lose his balance during chasing scene in the movie unlike in game where he can run like human does. This because Oni's head in movie apparently more heavier than rest of his body and given more realistic look. In real life, having a large head would hindered one's balance when running due to the weight.