Plot
As Tanjiro Kamado, Zenitsu Agatsuma, and Inosuke Hashibira assist Sound Hashira Tengen Uzui against Upper Rank Six siblings Daki and Gyutaro, they realize only a simultaneous beheading can kill them.[3] The trio successfully behead Daki, but Gyutaro wounds Tengen and stabs Inosuke with his poisonous sickle, retrieving her head. Zenitsu pushes Tanjiro away to save him from Daki's obi slashes, after which Gyutaro mocks Tanjiro for his inability to protect his friends and his demonic younger sister, Nezuko.
Gyutaro tries to persuade him to become a demon, but Tanjiro head-butts and stabs him with a wisteria-laced kunai. As he attempts to behead him again, Daki is then attacked by Zenitsu, using the last of his strength to reach her neck. Inosuke joins him, having survived by moving his internal organs upon being stabbed. Gyutaro removes the kunai and nearly kills Tanjiro, but Tengen intervenes and battles him to a standstill. Tanjiro summons his remaining strength, causing a strange mark to appear on his forehead that allows him to slash Gyutaro's neck, while Zenitsu and Inosuke cut through Daki's.
After the demons are beheaded, Tengen warns everyone to flee as Gyutaro's body explodes into waves of blood blades that destroy the city. However, Nezuko uses her Blood Demon Art to burn the blades and save those who were poisoned by burning away Gyutaro's blood. Tanjiro and Nezuko find the dying demons arguing about their defeat and insulting their relationship. He implores them to forgive each other in their last moments, just as Daki disintegrates. Gyutaro remembers their human lives before becoming demons as he disintegrates. In the afterlife, they reconcile upon remembering the promise they made to never be apart, walking to Hell together. Serpent Hashira Obanai Iguro arrives and commends Tengen for killing the Upper Rank Six, but Tengen intends to retire as Hashira and tells him about Tanjiro's potential.
In the Infinity Castle, Muzan Kibutsuji summons the remaining Upper Ranks – Akaza, Gyokko, Hantengu, Doma, and Kokushibo – and informs them of Gyutaro's death. He admonishes them for their failures and lack of purpose, before sending Gyokko and Hantengu on a joint mission to cripple the Demon Slayer Corps.
Two months later, Tanjiro has a dream about someone's encounter with a Demon Slayer from the past that wore the same earrings as him, before waking up from being comatose. While he undergoes rehabilitation, Zenitsu and Inosuke are summoned to individual missions. Because his swordsmith Hotaru Haganezuka has refused to forge him a new sword, Tanjiro must meet him at the Swordsmith Village to discuss the matter in person. He arrives with Nezuko and meets Love Hashira Mitsuri Kanroji. Village chief Tecchin Tecchikawahara reassures Tanjiro he will bring Hotaru back to build his sword.
While relaxing in hot springs, Tanjiro and Nezuko encounter Genya, a Demon Slayer from his Final Selection, who angrily rejects Tanjiro's attempt at friendship and storms off. Later, Mitsuri hints at Tanjiro about a "secret weapon" hidden in the village that can make him stronger before leaving. The next day, while searching for the weapon, Tanjiro meets Mist Hashira Muichiro Tokito and sees that seemingly with him is the same figure from his dream.
