Naosuke Gonbei is a supporting character from the Yotsuya Kaidan segment of the anthology series Ayakashi - Samurai Horror Tales. He initially appears as a servant to the ronin Tamiya Iemon and becomes entangled in a series of violent acts driven by his obsessive desires. His background is that of a low-ranking attendant, but his motivations stem from a consuming romantic fixation on Osode Yotsuya, who is the adopted sister of Oiwa. In order to eliminate his rival for Osode’s affections, Naosuke murders Yomoshichi Sato, Osode’s fiancé, on the same night that Iemon kills Oiwa’s father. Following the murders, Naosuke and Iemon conspire to stage the bodies as victims of bandits, allowing Naosuke to pressure Osode into a marriage of convenience. He agrees to a nominal marriage without immediate consummation, presenting a seemingly patient and respectful front to win her trust. His role in the story is that of an accomplice whose actions set off a chain of betrayals. Over the course of the narrative, Naosuke’s character undergoes a significant and tragic development. When Osode later learns the truth of Yomoshichi’s survival and Naosuke’s deception, she orchestrates a confrontation. During this climactic moment, Osode reveals through a dying note that Naosuke and she share the same mother, making them half-siblings. Overcome by shame and horror at his unknowing incestuous pursuit and his earlier murder, Naosuke commits suicide. As his final act, he asks Yomoshichi to carry out Osode’s wish for revenge against Iemon. His key relationships include his master Iemon, his object of desire Osode, and his victim Yomoshichi. Naosuke does not display any supernatural abilities; his actions are entirely human in nature, involving manipulation, deception, and violence. His development is a steep moral descent followed by a moment of devastating self-awareness that leads to his self-inflicted death.