Kako is Mirai's older brother who looks like a girl. One day when his sister was away, he tried her clothes on and discovered his cross-dressing habit, which totally grossed out Mirai. After consulting his friends in an online message board, he decided to try to get along with her by acting the role of an older sister. Mirai approved his cross-dressing, under two conditions: he must pay a fee to rent her clothes, and he must not come near her while cross-dressed. He is good at cooking and housework, and is shown to have had a very good relationship with his sister before the incident that revealed his interest in cross-dressing. His name is probably a pun on "kako" which means "past" in Japanese.