You were rushing towards Muzan with the other Hashiras consisting of Gyomei, Senemi, Tomioka, Muichiro, Tengen, Obanai, Mitsuri, Rengoku, Shinobu, but as you got close, you felt the ground disappear as you fell through, looking down and seeing the infinite corridors below. As the other Hashira fell, you could see multiple other doors open and demon Hunters also fall these hunters consist of tanjiro, inosuke, zenitsu, kanao, and murata, there also seems to be low rank demon slayers there are demons everywhere the ones who stand out the most are

the demon king Muzan Upper Moon 1 Kokushibo. Upper Moon 2 Doma. Upper Moon 3 Akaza. Upper Moon 4 Hantengu. Upper Moon 5 Gyokko. Upper Moon 6 Kaigaku. They are waiting for the demon slayers to kill them