Retto Wingate is a feared outlaw in the Wild West. He discovers and rescues the orphaned Isamu after the boy suffers a series of tragedies, taking him into his group alongside his son, Ned. Wingate recognizes Isamu's potential as a fighter and weapon user. He deliberately trains Isamu in combat and weaponry, molding him into an assassin. This training forms a core part of Isamu's upbringing under Wingate's guidance.

Despite Wingate's mentorship and Isamu's sense of debt, their relationship strains due to fundamental moral differences. Wingate exhibits ruthless pragmatism, exemplified when he murders the physician who saved his life simply because the doctor overheard plans for a heist. This act underscores his willingness to eliminate any perceived threat or liability without hesitation.

Isamu's inherent moral compass prevents him from becoming the killer Wingate expects, creating ongoing conflict. Wingate's influence endures as Isamu journeys through the wilderness, wrestling with the lethal skills he was taught and the ethical boundaries he refuses to cross. The tension between Wingate's ruthless outlaw philosophy and Isamu's innate sense of justice shapes Isamu's internal struggle regarding loyalty, obligation, and personal values.