- Hey, boy!
— Bacchus to Kiryu
Bacchus (バッカス, Bakkasu) is a former boxing trainer and vagrant who wanders around Kamurocho, drinking and racking up debt. During his time in Kamurocho, he befriends Kazuma Kiryu and teaches him fighting techniques for his Brawler style.
Bacchus initially seems patronizing towards Kiryu, simply calling him 'boy', exploiting him to escape from debt collectors, and pestering him to leave Kamurocho and become a professional fighter, despite constant refusals. He is initially reluctant to discuss his past, but ultimately reveals that he only calls his best students 'boy' and truly considers Kiryu his star pupil, the first since he left the United States.
Bacchus possesses a keen phobia of being stabbed in the ribs, and constantly warns Kiryu about it, due to his previous star student being killed by a mugger that way.
Before coming to Kamurocho, Bacchus was once a boxing trainer who operated a gym in the United States. When one of his trainees managed to knock out an opponent heavily favored by the Raymond Cartel, they began sabotaging Bacchus, poaching his student and burning down his gym. Bacchus took out a loan to rebuild it, but the mafia bought out his debt and drove away his clientele, leaving him penniless. After his last star pupil was killed in a mugging, Bacchus fled the U.S. and eventually came to Japan.
Bacchus first encounters Kiryu in Kamurocho while he is out drinking with Akira Nishikiyama. Upon witnessing Kiryu defeat a pair of drunkards, Bacchus commends Kiryu's talent and offers to become help him become a professional fighter. Later, Kiryu saves him from a pair of debt collectors, and Bacchus introduces Kiryu to Kamoji and Miss Tatsu and offers to teach him fighting techniques in exchange for his services as a bodyguard.
Bacchus's lessons consist of Kiryu defeating a series of hitmen sent after him, until a group of Raymond Cartel members arrive and attempt to recruit Kiryu as a fighter, revealing they had kept Bacchus alive to poach any talented pupils he found. After Kiryu refuses and fends them off, Bacchus finally accepts his refusal to become a professional fighter, and decides to return to the U.S. to resume training young boxers.
- A pair of boxing gloves displayed in the back of Bantam (previously called 'Bacchus') is a reference to him.
- Bacchus shares his name with the ancient Roman god of wine. This is appropriate given his apparent taste for alcohol.
- He appears to wear the same outfit as one of Shun Akiyama's alternate costumes, albeit with a different overcoat.