Tatsuyoshi is an employee of the Sonozaki family, who looks like a secret agent. He was more active in the past, but has settled down to become Shion's caretaker. He somehow knows both Teppei and Rina, and is aware of their lifestyles and badgering tactics. In Matsuribayashi-hen, he displays extreme strength and combat experience while raiding the Irie Clinic, frequently subduing members of the Yamainu.