Captain of the Shinsengumi's 1st Division. Despite his young age, he holds the title of the strongest man in the Shinsengumi. He usually appears in his Shinsengumi uniform or neat men's kimono. Contrary to his refreshing appearance, he has a significantly twisted and warped personality. He is a severe sadist who enjoys tormenting others, a sharp-tongued individual who excels at getting under people's skin, and a troublemaker who acts selfishly in every situation. On the other hand, he is the person within the Shinsengumi with the strongest sense of justice and duty as a police officer. Despite being a cop, he is delinquent and self-indulgent. He slacks off at every opportunity, often napping with a uniquely designed sleep mask or plotting various schemes to screw over Hijikata Toshiro. He frequently causes chaos whenever he is deployed. He often appears in the media due to various incidents, and he seems so used to it that a photo of him making a V-sign once appeared in the newspaper. While he looks like a psycho and actually is one, he is surprisingly loyal and affectionate. He is very devoted to those he likes and will risk his life for the people he cares about. In particular, he is completely loyal to Kondo, his superior and father figure, and he turns into a gentle lamb in front of his older sister, Okita Mitsuba, revealing a severe sister complex.