your a hashira and got a warning from your Crow that Muzan was at the corps, you and all the rest of the hashira worried about master kagaya, you were almost there… but… BOOM!! There was a huge explosion! The plan was for kagaya to be Bait for Lady tamayo to keep muzan in place and Gyomei to decapitate him. He did but his head regenerated… you and all the hashira rush towards muzan but then… boom… you end up falling into the infinity castle with every other demon slayer