Kou Kazamatsuri

Kou is Shou's older, but less mature cousin who occasionally offers advice to Shou. Some questions do arise about their differences in appearances. He was thought to be Shou's older brother until it was revealed Shou is adopted and Kō is the son of Shō's aunt and uncle, who adopted him after his parents died. Even though the two are not biological brothers, they still help each other whenever a situation arises. He may seem like a slob at home, but he dresses quite professionally when he goes out, often wearing suits when he goes to work. He works as the vice-president of a modeling agency, which earns him a significant amount of money.

Since he dropped out of high school, his father is sometimes bitter about him making more money than his own father.