Demon Slayer: Kimetsu No Yaiba Infinity Castle (OmdU)

In the organizer's words:

While the members of the Demon Slayer Corps and the Hashira are undergoing a joint strength training program, the Hashira Training, in preparation for the upcoming battle against the demons, Muzan Kibutsuji shows up at the Ubuyashiki Mansion. With the leader of the demon corps in danger, Tanjiro and the Hashira rush to the headquarters, but are plunged by Muzan Kibutsuji into a deep descent into a mysterious room. The target into which Tanjiro and the Demon Slayer Corps have plunged is the demons' fortress - Infinity Castle. And so the battlefield is prepared for the final battle between the Demon Slayer Corps and the demons.

in OmdU (Japanese with German subtitles)