Aoi is Sana's cousin and her parents own the apartment building that Sana lives in. She prefers to be called Aoi-chan instead of Aoi-san, despite the fact that she is a year older than Sana. She wears glasses and has a busty physique. She loves to read books and is very energetic and clumsy. She has a very high-pitched voice and has a child-like character.