Aoi is the tritagonist in the visual novel game Nine Hours, Nine Persons, Nine Doors. He is one of the nine participants in the second Nonary Game. He is voiced by Kisho Taniyama in the Japanese version and by Sean Chiplock in the English version.
Aoi has white spiky hair adorned with two black headbands, blue eyes, and a slim build. It is possible he dyes/bleaches his hair white like Phi and that his natural hair color may be black or brown.
He wears a thin black scarf, white tank top, black pants, black arm warmers, and brand new black and silver boots. Like the other players, he wears a bracelet on his left wrist.
In the past, a 15-year-old Aoi wore a dark private school uniform with a blue scarf, black pants, brown shoes, and a white messenger bag.
Aoi is very arrogant and cocky and has the tendency to use profanity whenever he is agitated. Despite these traits of his, this doesn't mean that he has a lack of empathy since he cares a lot about his sister and does care if the other survivors (except Ace and Kubota) get out alive. He always pushes forward and hates indecisiveness as shown near the beginning of the game where he tells the others to stop wasting time and move forward before their nine hours are up.
He is a lone wolf, and he has no spirit of cooperation, preferring to work by himself. He was very suspicious as he didn't trust the other participants (except Akane and Junpei), othe than himself. At some point in the Nonary Game, he advised Junpei not to trust the others as anyone can deceive him. Depending on the doors chosen, he strikes a small "friendship" during his nine hours with Junpei, presumably because he knows that Junpei will be the one to save his sister, and even gives Junpei a bookmark.
He describes himself as a "21st century guy" and says he has no reason to live by old-fashioned 20th century standards.
Aoi is intelligent, having knowledge about quite a bit of science, as exhibited during the kitchen investigation room.
Aoi may be gay, but it's left ambiguous. However, his sexual orientation is never a point of conversation or relevant to being trapped in a life-or-death game.
Aoi is based on the "Enthusiasm" Enneagram of Personality. Its fear is based on being trapped in pain and deprivation and its desire is to be satisfied and content, much like how Aoi fears losing his sister.
Despite all of this, its not made clear if Aoi's arrogant personality is a facade to keep up with Akane's plan but it is more likely his true personality as he shows a similar personality in the flashbacks to 9 years prior during the first Nonary Game.