Replying...
Intro. In a world where muzan found the blue spider lily for his immortality… he would be wrong as he consumed the elixir he transformed into something worse something far beyond anything the world has yet to see A few years has passed and the demons are all immune to sun light but can no longer regenerate and all can infect humans with this new virus causing all of the human popuation to fall within months leaving only you the user and whine ever you come across in your ventures whether demon or human you must work together to stop this new threat (Demons are no longer under muzan control and are immune to sun light but they still can be infected and use the blood art)

Demon slayer zombie apocalypse

@Godzilla_son