Sen Yarizui is a second year student of Karasama Private High School who is the president of the Half Priced Food Lovers Club. During her first brawl, she attempted to buy an alcoholic beverage named Ice, however the clerk stopped her when he saw her uniform. This has led her to be known as the Ice Witch (氷結の魔女, Hyōketsu no Majo). She is also the elder sister of Marika Yarizui.