WARNING: The following contains spoilers from Demon Slayer: Kimetsu no Yaiba the Movie: Mugen Train.
Demon Slayer's first film, Mugen Train, covers Chapters #54 through #66 of the manga, making it official canon. As such, the events of this unbelievably well-animated film will have palpable repercussions for Tanjiro and his friends in the anime's second season, which has just kicked off.
After a tremendous first season ended with Tanjiro, Inosuke, Zenitsu and Nezuko arriving at the train station that Mugen Train picks up at, the group is geared up for their greatest challenge yet with two of Muzan Kibutsuji's Demons lurking. The film also showcased the most action of a Hashira that the franchise has seen so far, and the fiery Kyojuro Rengoku left fans wanting even more of his soothing confidence. However, the world of Demon Slayer is rarely so kind.
Mugen Train Raises the Stakes for the Demon Slayer Corps
Mugen Train begins with Tanjiro, Inosuke and Zenitsu boarding a train together as they've been instructed to join the Flame Hashira, Rengoku, investigating the disappearances of citizens and fellow Demon Slayers who have boarded this particular locomotive. Tanjiro hopes to strengthen his own unique Hinokami Kagura technique -- which seems to have ties to Flame Breathing -- by studying under the Hashira, whom the boys quickly idolize after seeing Rengoku in action.
When a suspicious conductor comes through to punch their tickets, the proud Hashira and his new young apprentices are immediately enchanted into a deep sleep. Enmu, Lower-Rank One of the Twelve Kizuki, uses his Blood Demon Art to send the passengers into an unbreakable sleep, allowing his disciples to enter the dreams of his victims. If the invader destroys the target's spiritual core, the victim will never wake again.
While Inosuke's and Zenitsu's dreams are outlandish fantasies played for laughs, Tanjiro's dream is everything he's ever wanted. The young Demon Slayer finds himself in an alternate reality where his family was never slaughtered, and Nezuko is still human. He is skeptical of minor inconsistences, but he ultimately dismisses signals from the real Nezuko who is trying to wake him.
The Danger of Demon Slayer's Lower Moon, Enmu
When Nezuko's blood finally forces Tanjiro to acknowledge that his dream is not real, he determines that he must end his life in the dream to wake up. Steeling his resolve, Tanjiro leaves his family behind, accepting that the past cannot be changed, and once he wakes, he engages Enmu in battle. Tanjiro consistently breaks through the villain's Blood Demon Art by repeating the daunting task of turning his blade on himself to awaken again.
After the whole team snaps themselves out of their respective dreams, Rengoku, Zenitsu and Nezuko protect the sleeping passengers, while Tanjiro and Inosuke work to find and kill Enmu. With some near-flawless teamwork, Tanjiro and Inosuke defeat Enmu, even after the Demon reveals that he's fused himself into the train. Unfortunately, Tanjiro is stabbed in the process, leaving him unable to fight when more trouble arrives in the form of Akaza. Upper-Rank Three of the Twelve Kizuki, Akaza is one of the most powerful Demons in existence.
With Tanjiro severely wounded and Inosuke completely outclassed, Rengoku battles this new threat alone. After a prolonged and spectacular clash, the Flame Hashira is mortally wounded by the Upper-Rank Demon. Still, with the sun quickly rising, Akaza flees to save himself as Tanjiro angrily screams that Rengoku is the rightful winner of the battle since he saved everyone while the Demon ran away as soon as the advantage of the night began to vanish.
In his final moments, Rengoku offers Tanjiro and his friends some words of encouragement. The dying warrior instructs his would-be apprentice to seek out the previous Flame Hashira -- Rengoku's father -- if he wants to learn more about Hinokami Kagura. Tanjiro struggles with feeling helpless against such a powerful enemy as Inosuke encourages him to keep moving forward.
Season 2 Will Be the Start of a New Era for Demon Slayer
The events of Demon Slayer: Mugen Train were a harsh dose of reality for Tanjiro and his fellow Demon Slayers. A seemingly invincible Hashira was brought down by an Upper-Rank Demon who is not even the most powerful in Muzan's forces. The boys must get stronger in a hurry because they may not have a Hashira to protect them the next time Akaza or another Upper-Rank appears.
Now carrying the weight of Rengoku's legacy and guilt over his death, Tanjiro has a lot to prove. Expect the young hero to fulfill his honorary master's last wish by visiting his family. Unfortunately, the father of the deceased Hashira is an intense and callous man who may not feel inclined to help another Demon Slayer, much less the one his son died protecting. Still, Tanjiro will be eager to master his unique technique to honor Rengoku, save Nezuko and defeat Muzan -- who put a target on Tanjiro's back.