Aoi is a participant in the death game featured in the Ghost House arc, identifiable by her shaggy blue hair and a consistently nervous, withdrawn expression. She is often seen hunching forward, avoiding eye contact, and physically shrinking into herself when surrounded by others, which makes her stand out even among the other players dressed in the classical black-and-white maid outfit. She has blue eyes and appears to be an adolescent.

Aoi possesses an extremely shy, anxious, and socially withdrawn personality. She speaks very little, and when she does, her voice is barely audible. She struggles to assert herself in any situation and relies heavily on others for reassurance and a sense of safety. In quieter moments away from the immediate danger, she enjoys reading and knitting, activities that suit her reserved nature. She also has a strong dislike for most forms of communication.

When asked about her reasons for entering the deadly game, Aoi explains that she had no other choice. She provides no further details about her life outside the game, but her vague explanation, combined with her poor social skills and lack of confidence, leads other characters to speculate that she may have been driven to participate due to economic hardship and an inability to survive through conventional employment.

Within the story of the Ghost House mansion, Aoi serves as an example of a vulnerable and inexperienced player. She identifies this game as her first-ever death game, immediately establishing her lack of familiarity with the life-or-death stakes. During the group's initial exploration, she becomes visibly distressed by the constant danger and clings tightly to the more capable protagonist, Yuki, staying close to her for physical and emotional reassurance. Aoi survives the early stages of the game, including a trap that results in another player's death, but she consistently shows signs of overwhelming fear and does not take initiative during any decision-making processes.

Aoi's most significant relationship is with Yuki, the de facto leader of the group. Aoi relies on her almost entirely for safety, often clinging to her physically as they navigate the mansion's dangers. Yuki views Aoi as a fragile person who represents the type of player with no other options in life, forced into the game by desperation rather than choice. Aoi has minimal direct interaction with the other participants, remaining largely in the background and failing to form any other notable bonds before her death.

Due to her early demise, Aoi undergoes very little character development. She remains consistently fearful and dependent from her introduction to her final moments. Her arc concludes in a hexagonal chamber containing six levers, which transforms into a deadly minigame. As saw blades descend from the ceiling, chaos ensues among the players as they struggle to free themselves from restraints. Unable to secure a key in time and lacking the resolve to sacrifice herself for others, Aoi is killed by the descending blades. Her death is marked by her first and only loud scream, a moment that sharply contrasts with her usual near-silence throughout the game. After her death, her body undergoes the game's Preservation Treatment, leaving behind white, cotton-like residue instead of visible blood.

Aoi does not possess any notable combat abilities or specialized skills relevant to surviving the death game. Her primary traits are her quiet demeanor and her hobbies of reading and knitting, which do not aid her in the lethal challenges she faces.