Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train - Ending Explained

"Mugen Train"'s plot unfolds in two distinct acts. The first antagonist is Enmu, the Lower Rank One demon, who traps the heroes in idyllic dreams. Tanjiro dreams of his family being alive, Zenitsu dreams of a date with Nezuko, Inosuke dreams of being a heroic cave-exploring leader, and Rengoku dreams of a past conversation with his father and brother. Nezuko, being a demon, is unaffected and uses her Blood Demon Art to help awaken the others. Tanjiro discovers that the only way to escape the dream world is to die within it, forcing him to repeatedly and traumatically slit his own throat in the dreamscape to wake up.

After a prolonged battle, Tanjiro and Inosuke locate Enmu's real body, which has fused with the lead train car. They sever his spinal column, killing him and causing the train to derail. Just as the heroes believe they have won, a far greater threat appears: Akaza, the Upper Rank Three demon. Akaza's arrival marks a significant escalation in power. He almost kills Tanjiro before Rengoku intervenes. The film's climax is the spectacular battle between Rengoku and Akaza. Despite his incredible skill, Rengoku is unable to overcome Akaza's instantaneous regeneration. Akaza fatally wounds Rengoku by punching a hole through his solar plexus. However, Rengoku uses his last ounce of strength to hold Akaza in place, attempting to trap him until sunrise. Akaza is forced to sever his own arms and flee into the woods as the sun appears, prompting a grief-stricken Tanjiro to scream at him, declaring Rengoku the true victor. Rengoku dies peacefully, smiling as he sees a vision of his mother, who praises him for fulfilling his duty. His death serves as a brutal lesson for Tanjiro, Zenitsu, and Inosuke about the power of the Upper Rank demons and solidifies their resolve to become stronger.

While the film's narrative is quite direct, some interpretations delve into its deeper cultural and philosophical underpinnings. One perspective reads the story through the lens of Japanese spiritual traditions like Shinto and Buddhism. The demon slayers act as spiritual purifiers, cleansing the world of malevolent forces, akin to the Shinto ritual of 'harae'. Rengoku's character, with his acceptance of impermanence and focus on duty, can be seen as embodying Buddhist and Confucian values, respectively. Another interpretation focuses on the psychological aspect, particularly through a Freudian lens. The dream sequences can be analyzed as manifestations of the characters' unconscious desires and traumas. Tanjiro and Rengoku's dreams tap into a longing for family and validation, while Zenitsu and Inosuke's dreams reflect more primal desires for romance and dominance, showcasing the different facets of their psyches.