Demon Slayer: Kimetsu no Yaiba – The Movie: Mugen Train

Haruo Sotozaki directed the film, which ufotable produced together with Aniplex, adapting the Mugen Train portion of Koyoharu Gotoge's manga and serves as a sequel to the anime's first season. Toho released it in Japan on October 16, 2020, with international screenings following through mid-2021. Attendees of early showings received an exclusive 84-page booklet, Rengoku Volume 0, capped at 4.5 million printed copies, containing a special one-shot and other bonuses. The work was later recut and aired again to open the show's second season, with added content.

The four young slayers ride the train to back Kyojuro Rengoku as he hunts a demon responsible for many deaths among both fighters and ordinary people. Once aboard, every one of them is drawn into a deep slumber by Enmu, ranked Lower One, who tasks four sleepless passengers with entering their dreams to ruin the spiritual cores within. Sensing the illusion, Tanjiro escapes it after his father appears to him, and Nezuko cuts the intruders' link while waking the others.

Tanjiro beheads Enmu, but the demon endures by merging his head into the train itself. Kyojuro keeps the passengers safe while sending Tanjiro and Inosuke after the neck, which they find and cut to finish him. Then Akaza, the third of the Upper Ranks, arrives and fatally wounds Kyojuro in single combat before retreating at sunrise. Calling the demon a coward and declaring Kyojuro the real winner, Tanjiro listens as the dying Hashira offers the youths encouragement and then passes away.

The film drew strong reviews, with praise for its music, characters, and action, and it earned numerous awards. It grossed over 500 million US dollars worldwide, becoming the year's top earner for 2020 and the first production made outside Hollywood to lead a global annual box office. It also surpassed Spirited Away to claim the all-time record for a Japanese film, a mark the Studio Ghibli work had held for nearly two decades, and stands among the highest-grossing animated films ever made.