Kotaro Kakinouchi is a wealthy heir of the Kakinouchi conglomerate and a classmate of Mayura Daidouji. He is characterized as a flirtatious ladies man who often pursues pretty girls, but he also has a quick mind and sharp intuition. His personality balances playful charm with sudden bursts of aggression, and he frequently provides comic relief. In the anime, he appears in a limited number of episodes, where he spends time with Loki and the group and has notable interactions with the goddess Hel. In the manga, his role is more developed: Loki nicknames him Kou, and he proves to be a valued asset, nearly as skilled a detective as Loki himself. Kotaro's key relationships include his friendship with Loki and his connection to Mayura as a classmate. He does not possess supernatural abilities, but his wealth and perceptiveness occasionally support the group's efforts.