Kamui 神威 is a member of the Yato Tribe 夜兎族 and the son of Umibouzu 星海坊主, older brother of Kagura 神楽 and Housen 鳳仙's pupil. His excellent fight skills helped him become Captain of the 7th Division of Harusame's Thunder Guns 春雨の雷槍, the most powerful combat unit within the Harusame 春雨 group and Overlord of Yoshiwara. Since defecting from the Harusame, he no longer holds these positions.
Kamui firmly believes that the Yato are to remain on the battlefield and shows his disapproval of Housen staying locked up in Yoshiwara. Because of this belief, he shows no pity towards family or subordinates as a sign of weakness is unacceptable.
He tried to revive the abandoned tradition of a Yato clansmen killing their own parent to pove their strength, although failed to successfully execute it.
Kamui 神威 used to live with his father Umibouzu 星海坊主, sister Kagura 神楽 and mother, but would soon leave their home. He then became the disciple of Housen 鳳仙, after his attempt on taking over his own father's position as the strongest failed. Kamui later turned against his previous master, Housen, but their fight was interrupted by Kamui's underlings.
During the The Blaze of Yoshiwara chapter, Kamui 神威 discovered Sakata Gintoki 坂田 銀時's amazing fighting abilities during his showdown with Housen 鳳仙 while hanging around as a passive observer, and subsequently staked him as his own prey, i.e vowed to fight him one day, after Gintoki has fully recovered from his injuries during the battle with Housen 鳳仙.
In the manga, Kamui was tricked by the Harusame 春雨 into thinking they were going to kill off Takasugi Shinsuke's Kiheitai 鬼兵隊 and Takasugi himself, when they were actually after the 7th Division and Kamui, believing he had grown too strong and unreliable for them to control. As Kamui was captured, Takasugi took on the duty of executing him infront of the Harusame, however Takasugi freed Kamui instead, attacking the Harusame head-on, with help from both the 7th Division and the Kiheitai. After killing off the Harusame, Takasugi and Kamui together headed for Earth.
- Kamui's hair was actually black in a flashback in Episode 42 of the Gintama anime, and also in an ending before the Yoshiwara is Burning arc. After the ending credits of Episode 146, Ginpachi-sensei answered a fan letter about Kamui's black hair by throwing it in the Rejection Box.