Només quatre aspirants han superat la tria final. Cadascun d'ells rebrà un uniforme i un corb Kasugai, que servirà d'enllaç amb l'organització. En acabat, els faran triar una peça d'acer "tamahagane" amb què forjaran la seva espasa, la "nichirin". En Tanjiro, al límit de les seves forces, aconsegueix tornar amb penes i treballs a casa de l'Urokodaki, on l'espera una sorpresa.

Ja fa dues setmanes que el Tanjiro, el Zenitsu i l'Inosuke són a la mansió de la Shinobu Kocho, la Pilar dels Insectes. Quan ja estan gairebé del tot curats, el Tanjiro i l'Inosuke comencen la rehabilitació, però aviat es desanimen perquè els exercicis que han de fer són molt durs. El Zenitsu, que comença uns dies més tard, es motiva en veure's envoltat de noies.

El Tanjiro es recupera a la Mansió Papallona, on entrena la tècnica de la Concentració Total per aprendre a mantenir-la de dia i de nit. La seva companya de promoció, la Kanao, li fa fer exercicis que el deixen en evidència, però, al cap d'uns dies, l'entrenament comença a donar fruit. El Zenitsu i l'Inosuke, inspirats per la constància del Tanjiro, també reprenen les sessions d'entrenament.

After the Mugen Train incident, Akaza visits Muzan Kibutsuji. Guided by a crow, Tanjiro Kamado heads off to the Rengoku residence to convey Kyojuro Rengoku's last messages to his father and little brother. Tanjiro's group return to the Butterfly Mansion.

An Upper Rank Demon has been defeated for the first time in a hundred years by Uzui, Tanjiro, and his comrades' effort. This news causes a ripple effect not only among the members of the Demon Slayer Corps, but also the Upper Rank Demons, who have been summoned by Muzan Kibutsuji. Meanwhile, Tanjiro is recovering at the Butterfly Mansion when he discovers that he has upset his swordsmith Haganezuka after chipping his sword and decides to head to the village where the swordsmiths live to talk to him in person.

Tanjiro intervenes during an argument between a pillar and an apprentice blacksmith and learns of the existence of an amazing training method.

Tanjiro begins his training with Yoriichi Type Zero and is pushed to the limits by Kotetsu's relentless coaching and extreme training. Through this experience, Tanjiro masters a new skill of predicting where the opponent's next move will hit by using his sense of smell. During his training, Tanjiro lands a blow on Yoriichi Type Zero and ends up destroying it, but a sword from over 300 years ago appears from inside...

Two simultaneous fights continue, Tanjiro, Nezuko and Genya against Hantengu and Tokito against Gyokko. Genya began to show a demonic form. Tanjiro asks him to look for Hantengu's real body, but memories of the past begin to plague Genya.

Genya aims for the neck of the fifth demon that split off from Hantengu, but the demon's neck is shockingly hard, and his sword snaps in half in his attempt to strike it. His gun is also ineffective and Genya is driven into a corner. Realizing that he is unable to sever the neck by himself, he entrusts defeating the fifth demon, which is believed to be the main body, to Tanjiro. Taking on Genya's will, Tanjiro wields his sword against the fleeing demon...

Armed with his memories, Muichiro feels powerful and invincible, convinced that the demonic fifth moon has no chance against him.

Tanjiro continues the fight against Hantengu. Amidst all his injuries and the Superior Four's skill, will he be able to defeat him? As the battle draws to a close, the Demon Slayer Squad must race against time to end the fight before dawn.

The Hashira, Sanemi and Iguro, along with their comrades head to an abandoned castle on top of a mountain for a mission, while Tanjiro is being treated at the Butterfly Mansion for the wounds he suffered at the Swordsmith Village. Later on, the Hashira gather at the Ubuyashiki Mansion to hold a Hashira meeting, where Muichiro reveals how the marks manifested. In an effort to strengthen the entire Demon Slayer Corps from the bottom up, the Hashira Training begins...