Kou is a college friend and classmate of Akihito Takaba and remains one of his close companions from university. With a playful sense of humor, Kou enjoys teasing his friends, exemplified when he gifts Akihito zebra-printed hi-cut briefs for his birthday along with a note suggesting it would surprise Asami. During another birthday lunch with Akihito and their mutual friend Takato, Kou delivered his present before promptly rushing back to work. He continues to maintain his friendship with both, often socializing together, and serves as a supportive figure within Akihito's circle.