Ryujiro was part of Tomonoshin Shibui's gang and were patrons in the teahouse in episode one.
Impatient with Fuu's clumsiness, Tomonoshin ordered Ryujiro to use his new sword to cut off part of Fuu as a "lesson". Mugen interferes when Fuu offers Mugen 100 free dumplings for helping her. Ryujiro picks a fight with Mugen and ends up getting half of his right forearm severed by Mugen. Enraged, he burns down the teahouse, killing Tomonoshin.
Ryujiro returns in episode two to seek revenge on Mugen, Jin, and Fuu, whom he blames for him losing his arm, and to satisfy his desire to see people suffer. He frees Oniwakamaru from jail for use as a bodyguard, kidnaps Fuu to use as a hostage, uses Hotaru to seduce and poison Mugen, and hires a very skilled assassin to kill Jin.