Ikuko (育子, Ikuko) is the executive committee chairman of the athletic meet (undoukan). She appears to be masochistic and is seen tied up with ropes. She announces the names of those who must participate in each round of the game and explains, sometimes, the rules.
She is dressed like a cheerleader and her joints are those of a doll. She is similar to the character from the manga Kamimaro used to draw.