Kamui, a battle-driven member of the Yato Tribe, is the son of Umibouzu and Kouka, and elder brother to Kagura. His childhood on Rakuyou involved managing household chores and caring for his infant sister while his mother lay bedridden. With his father absent searching the universe for a cure, Kamui endured bullying from others, holding back his fists after being scolded by Umibouzu for using his strength against the weak. This restraint shattered when Kagura was attacked and Kouka's health worsened. Influenced by Abuto of the Harusame, Kamui embraced the pursuit of strength above all. He later attempted to kill his father to prove his power and revive the Yato patricide tradition, costing Umibouzu an arm. Following this confrontation, Kamui left his family, becoming a pupil of Housen and rising to captain the Harusame's 7th Division before becoming its admiral. He wears a near-constant cheerful smile, even in combat, as a sign of respect, masking a battle-obsessed and sadistic nature. Kamui believes Yato belong on the battlefield, disdaining those who settle down like Housen in Yoshiwara. He avoids killing women and children, rationalizing that women may bear strong opponents and children possess future potential, contrasting his violent tendencies though he values fair fights against worthy foes. Trauma over his mother's death hardened into the belief that emotional family ties are weakness, leading him to initially reject connections with his father and sister. Yet underlying care persists, such as instructing Gintoki to ensure Kagura grows stronger. His relationships reflect this complexity. With Kagura, he oscillates between dismissal and protectiveness. He openly declared her weak and tried to kill her upon their reunion, yet saved her multiple times, including during the Shogun Assassination arc. After their Rakuyou battle, he found peace with her, resting on her lap while imagining their mother, and taught her Qiqong manipulation to extend her lifespan. Resentment towards Umibouzu over Kouka's death fueled their conflicts, though they acknowledged lingering familial bonds after their Rakuyou fight. Kamui respects strength, forming an alliance with Takasugi Shinsuke after Takasugi saved him from a Harusame execution attempt. Abuto serves as his steadfast subordinate and moral anchor, commanding Kamui's implicit trust. Physically, Kamui possesses vermilion hair tied in a braid with a distinctive antenna-like lock, blue eyes, stands 170 cm tall, and weighs 55 kg. He typically wears a traditional Chinese martial arts uniform: a black-and-white top with gray pants. His Yato heritage grants immense strength, speed, endurance, and potent regeneration, allowing him to withstand debilitating poisons and heal rapidly. His combat style blends acrobatics with precision strikes, enabling him to overpower foes like Housen. When severely threatened, he may enter a self-destructive "Yato mode," drastically increasing power at the cost of rationality, triggering indiscriminate attacks. Kamui participated in the Silver Soul arc, aiding former enemies against a common threat. He later visits Kagura periodically, sustaining a connection with his family despite his earlier rejection of emotional bonds.