Aoi is a mysterious, self-proclaimed 16-year-old girl who Otoo meets on his travels to find his missing wife. He brings her back to Wagnaria where she starts working as a waitress and living in Wagnaria's attic. While she has great confidence in herself, during work she is an unhelpful troublemaker who gets yelled at by other staff members, especially Souta. Since she is in training, her position among the staff is low, which she complains about. She is bad with dealing with Souta's constant complaints about her, but she does write down some of his suggestions (along with idle complaints). She yearns for the idea of having a family, especially towards Otoo whom she sees as an ideal father figure, and goes as far as to apply to be adopted by him. Her favorite food is natto.