Tsukumo's older sister, Yuki's relative and also a Zweilt guardian. Her ring transforms in a huge sword. She attends the same high school as her brother, where their closeness make all the girls jealous of her. She is very fond of Yuki (whom she calls Yuki-chan), telling him that "He is a person who is to kind for their own good" and asking her to refer to her in a more close way (Touko-chan) instead of calling her Touko-san.