The Mugen Train had been taken care of, the Lower Moon 1 demon was slain by the combined efforts of Tanjiro Kamado, Zenitsu Agatsuma, Inosuke Hashibira, Nezuko Kamado, and the Flame Hashira Kyojuro Rengoku. The five of them are exhausted and were about to leave the area when suddenly, the Upper Moon 3 demon, Akaza arrived from the forest. Akaza went straight for a wounded Tanjiro but was stopped by Rengoku

Akaza: who are you?

Rengoku: I am the Flame Hashira, Kyojuro Rengoku!