Doushin

Doushin is gentle and paternal around his adopted children despite having spent much of his life killing. His affection for them is genuine, and the temple provides him with an identity separate from the violent persona audiences know as Kidomaru.

He is burdened by the life he has led and eventually wants to abandon killing altogether. Rather than treating violence as something admirable, Doushin understands the damage it has done to him and hopes to remove the children from the environment surrounding Rengokukan.

His willingness to change becomes more important than his past crimes. The children see the person who feeds, shelters and protects them rather than the arena's feared champion.

Doushin is an experienced professional killer and formidable close-range fighter. In Rengokukan he fights under an oni-themed disguise as Kidomaru and wields a heavy kanabo.

His history as an assassin gives him practical killing experience far beyond that of an ordinary arena contestant. He survives long enough in Rengokukan to become its champion, demonstrating both physical power and combat proficiency.

No supernatural abilities are established for him. His danger comes from conventional martial ability, strength and years of lethal experience.

Doushin was once a hired assassin awaiting execution. The organization behind Rengokukan arranged his release on the condition that he fight in its underground arena, turning a condemned killer into one of its star attractions.

Away from the arena, Doushin takes responsibility for numerous orphaned children at a temple. Kagura and Shimura Shinpachi eventually discover the connection between the children's guardian and Kidomaru.

Doushin decides to stop killing and flee Edo with the children, but Rengokukan refuses to allow its champion to leave. He is killed by Onijishi, the Dakini fighter brought in to replace him. His children subsequently ask the Yorozuya to destroy the arena, leading Gintoki into a direct confrontation with Rengokukan.

Doushin's adopted children are the center of his life outside Rengokukan. He shelters and cares for them at his temple, and his desire to give them a better life drives his decision to abandon the arena.

Sakata Gintoki, Kagura and Shimura Shinpachi become involved after discovering the reality behind Kidomaru and the children he supports.

Onijishi is the Dakini fighter selected as Doushin's replacement. When Doushin attempts to leave Rengokukan behind, Onijishi kills him and assumes his position as the arena's champion.

Sougo Okita and Toushirou Hijikata investigate Rengokukan from the Shinsengumi side, bringing their efforts into the same conflict surrounding Doushin and the illegal arena.