Airi Akitsuki is a central character originating in the visual novel "Oni Chichi ~Manamusume Kyousei Hatsujou~" and its adaptations. She is one of two daughters of Kayoko Akitsuki. Airi shares no biological relation to her older stepsister, Marina Akitsuki, as they have different fathers, though this remains largely unexplored. Her family dynamic changes when her mother marries Kouzou Akitsuki, her stepfather, who is a chemistry teacher with a doctoral degree at Airi's school. Physically, Airi has blonde hair, typically styled in distinctive French braid twintails, and blue eyes. Her appearance is partly inherited from her biological father. She possesses a slender build with a bust size comparable to her older stepsister despite being slightly shorter than Marina. Regarding personality, Airi exhibits traits of a tsundere archetype, displaying a stubborn, rebellious, and free-spirited nature. She openly expresses hostility and distrust towards her stepfather Kouzou, contrasting with Marina's more accepting demeanor. Her personality is characterized as somewhat selfish and resistant to authority figures she dislikes. Her experiences form the core storyline. Kouzou, harboring illicit desires towards his stepdaughters, develops an aphrodisiac drug in his laboratory. He uses this substance to overcome Airi's resistance, enabling his sexual abuse of her. This abuse goes beyond physical violation; Kouzou also engages in voyeuristic activities like recording Airi while she showers or changes clothes and collects their worn underwear. Airi's best friend, Sana Kuranaka, who bears a striking physical resemblance to her, also becomes a victim of Kouzou's drug and subsequent abuse after being brought to the Akitsuki home. Information regarding significant character development, redemption arcs, or substantial changes in her circumstances across various sequels or spin-offs is not detailed. Her relationships are defined primarily by familial ties: her mother Kayoko, often absent due to work; her stepsister Marina; and her stepfather Kouzou, the source of her trauma. Her close friendship with Sana Kuranaka is noted, though tragically intertwined with their shared victimization. There is no indication of a romantic partner or significant positive relationship developments outside this core circle.