Akasaka Mahiru

Cousin of the protagonist. Is a teacher at the school where they go.

As someone far apart in age, from the past, has been admired by the protagonist and Kotoha.

During the days of absence of the serious and diligent parents, she has cooked meal for both of them, sometimes.

Is also quite skillful at games and has beaten the protagonist thoroughly, at times. Is something like a "gamer girl".

Because of being originally from an all-girls high school, doesn't have any relationship with men. Due to having superficial knowledge regarding sex, is very interested in things related to sex.