He is a member of the Port Mafia's Flags in charge of a gemstone black market. Aiding Adam in the investigation, he learns about his existence throughout the case and how he is connected to Verlaine. On the surface, Chūya is a temperamental and rather arrogant, blunt man. He revels in fighting, happy to show off his combative ability, and taking great pride in his reputation as the mafia's strongest martial artist.