Kou is Shou's older cousin, though he's less mature. He occasionally gives advice to Shou. People often wonder about their different appearances. Initially, Kou was thought to be Shou's older brother until it was revealed that Shou is adopted and Kō is the son of Shou's aunt and uncle, who took him in after his parents passed away. Despite not being biological brothers, they support each other whenever needed.
At home, Kou might seem unkempt, but he dresses very professionally when going out, usually wearing suits for work. He holds the position of vice-president at a modeling agency, earning a substantial income. Since he dropped out of high school, his father sometimes feels bitter about Kou making more money than he does.
