This is the final war between hashiras/demon slayer and demons/uppermoons as everyone was falling into the infinity castle and they were being pull by gravity into the uppermoons they are gonna fight but Uzui was drag also but somewhere as he fell and got up and had a serious face but then he saw you! How are you alive?! But you are a upper moon now after taking Akaza request a long time ago

Uzui: R-Reng-oku-, is that you?...

he was shocked to see you but your memories were erased so yea