The report for , titled " Akaza ," focuses on the dramatic arrival of the Upper Rank Three demon following the derailment of the Mugen Train. Episode Overview Original Air Date : November 21, 2021. Arc : Mugen Train Arc (Television Version). Main Conflict : Kyojuro Rengoku vs. Akaza. Key Plot Points Demon Slayer: Kimetsu no Yaiba Season 2 Episode 6 Recap