A high school senior, Nee-san is the head of the Model Club. Despite her short stature, her underclassmen (and some adults) call her Nee-san. In contrast to this, her classmates call her Chibiko. Nee-san is generally vulgar, outrageous and is a big troublemaker. She likes being the center of attention and making fun of her fellow club members.

Surprisingly, Nee-san is good at academics, cooking and shogi. A model of a castle stands on her head.