Kimetsu no Yaiba: Mugen Ressha-hen  

Demon Slayer: Kimetsu no Yaiba Mugen Train Arc, Kimetsu no Yaiba Movie: Mugen Ressha-hen (TV), 鬼滅の刃 無限列車編, Demon Slayer: Kimetsu no Yaiba - Mugen Train Arc, Kimetsu no Yaiba: Mugen Ressha-hen (TV), ดาบพิฆาตอสูร : ศึกรถไฟสู่นิรันดร์ (TV), 鬼灭之刃 无限列车篇

The Demon Slayer Corps is investigating a series of unexplained disappearances on a specific train. They suspect that a demon may be responsible and have dispatched one of their top members, Kyoujurou Rengoku, to eliminate the threat before boarding the Mugen Train. However, the plan to join the train is delayed due to an attack by a lesser demon who is targeting mechanics and endangering a kind elderly woman and her granddaughter. Tanjirou Kamado, Inosuke Hashibira, and Zenitsu Agatsuma are sent to assist Rengoku in eliminating the threat before they can board the train. The demon has already devised a cunning plan to use its power held by the Twelve Demon Moons to obliterate everyone on the train, including the passengers, in a spectacular display of strength.

Mugen Ressha-hen adapts chapters 54 to 66 of the manga. The first episode is original to the anime.