Ranbō is an elderly martial artist and monk. Seven years before the main events, he offered sanctuary to the fugitive Juzo Fujimaki after Fujimaki fled Nara following an incident. Throughout Fujimaki's time in hiding, evading authorities and grappling with his past actions, Ranbō provided refuge at his residence. He allowed Fujimaki to continue his martial arts training, specifically refining his skills in the Takemiya-ryū style, acting as his mentor during this exile.

Physically, Ranbō is a bald man, often with facial hair, aligning with traditional depictions of monastic figures. His role centers on providing this sanctuary and guidance to Fujimaki.