Sousuke Kawara (河原 宗介 Kawara Sōsuke) is the 12 year old pubescent son of Heitarou and heir to the Kawara Clan's leadership who intervenes when Ishimatsu comes to collect Osuzu's father's business deed, succeeding only in getting her taken away. He joins forces with Jin to rescue but fails as Mugen is guarding the brothel.
The night after he goes to see Osuzu again and blows a gasket when a customer puts his hands on her. The man is Rikiei Nagatomi, but Sousuke does not know than when he draws his sword and stabs him to death. His, father Heitarou commits sepukku on his account. Rikiei mocks Heitarou while Sousuke defends him. Upon the Nagatomi Clan's defeat, he assumes his father's position.
Sousuke has brown hair that is tied up in the back of his head with a strand of hair hanging on the left side of his face. His eyes are the exact same color as his hair and he wears a light blue kimono.
Rikie is hasty and impetuous, which is not a surprise for his age and the shame his father has to endure. He has strong feelings for Osuzu that he shows this when he intervenes with Ishimatsu when he comes to collect her father's business deed.
- The name Sousuke means "religion, sect, denomination, main point, origin, essence" (宗) (sou) and "forerunner, herald" (介) (suke).
- Sousuke's surname Kawara means "river, stream" (河) (ka) and "field, plain" (原) (hara/wara).