Aono Ohki, later Aono Sasaki, is the younger sister of Tsuyoshi Ohki. She attends Jinbou Elementary School with her brother, and is in second grade during the first season. She is friendly with Sana, who convinces her that an egg she bought hatched into a chick (to Hayama's disapproval). When the chick grows up, she is forced to part with it do to it crowing in their small, cramped apartment.
After her and Tsuyoshi's parents divorce, she and her brother live with their mother. She is not as affected by the divorce as her brother, but now Tsuyoshi has to compensate and act as both a father and brother figure to her.