As Tanjiro and the others are devoted to their rehabilitation training, the absolute master of the demons, Muzan Kibutsuji, gathers the Lower Ranks of the Twelve Kizuki. The demons, too, are preparing to make their next move. As training draws to a close, Tanjiro has improved to the point where he can fight on equal terms with Kanao. Just then, he receives word of a new mission from his Kasugai Crow.
Following Rui's death a few months earlier, the remaining five Lower Moons are summoned into a space warped and controlled by a demoness with a biwa. They don't recognize Muzan Kibutsuji, as he masked his aura and appearance to that of a woman until he commands them to kneel. He informs them that the Lower Five, Rui, has been killed and demands to know why the Lower Moons are so weak. He continues that they shouldn't be satisfied with merely being among the Twelve Kizuki, that they must devour more humans and gain more powerful which is how they can become useful to him. He continues explaining to them that the Upper Moons have remained unchanged for over a century and only they have ever killed Hashira level Demon Slayers, and asks the remaining Lower Moons how many times which they have been replaced. Kibutsuji kills all except Lower One for doing things he deemed disrespectful. Kibutsuji asks for Lower One's last words and he says that it is an honor to die by his hand and thanks him for letting him witness the others' agony.
Kibutsuji accepts this as a valid answer and infuses Lower One with a large amount of his blood to strengthen him and tells him to be useful to him by killing a Hashira; he concludes by stating that he'll give him even more blood if he can kill the Demon Slayer wearing hanafuda earrings (Tanjiro). The meeting concludes and Muzan leaves while Lower One is de-summoned from the space saying that more blood would be a dream.
In the present day, a Kasugai crow wakes Tanjiro, Zenitsu, and Inosuke with an assignment - to the Infinity Train, where 40 Demon Slayers have disappeared, and slay the demon there. Tanjiro encounters Genya from Final Selection while walking, who has a more muscular form but is ignored by him. Tanjiro visits Aoi, thanking her for helping him, but she tells him not to, saying she survived the Final Selection by luck, and that she was too cowardly to go into battle. Tanjiro says that he'll carry her feelings into the battlefield for her, thanking her again. He also says goodbye to Kanao, who flips a coin to determine if she should talk to him. When the coin lands right, she tells him goodbye and explains she uses the coin to decide things she hasn't been ordered to do, since she can't decide for herself. Tanjiro takes her coin and says if it lands heads she'll listen to herself and make her own choices.
It lands heads and asks how he made it do that since she didn't see him cheat, but Tanjiro smiles and says it just did and he would have flipped it as many times as he needed for it to land heads. Just before the boys leave, Tanjiro sees Giyū and thanks him for helping. Giyū tells him to thank him by slaying demons, which Tanjiro promises. The boys make it to the train station but Inosuke causes a scene as he, along with Tanjiro, has never seen a train. They attract the attention of the police and flee. Zenitsu explains the Demon Slayers aren't recognized by the government, which doesn't know that demons exist. They jump onto the train as it leaves. On the train with them are Rengoku and the Lower One of the Twelve Moons.
Characters in Order of Appearance
- In the anime, Giyu arrives at the Butterfly Mansion to visit Tanjiro before he sets off on his mission. However in the manga, it does not mention Giyu visiting Tanjiro, and only depicts the boys bidding the girls farewell.
- In the anime, Kanao was shown to be surprised at Tanjiro's actions and holds the coin near her heart, after which the scene switches. In the manga, Kanao was called by Kiyo to tell her that Shinobu was looking for her. Kanao was still thinking about Tanjiro, and Kiyo's sudden arrival caused her to be surprised and fall to her face. This scene was not shown in the anime.