My swap au for demon slayer. Thank my cousin for me posting this, cause her interest made me think someone else might enjoy this. What would happen if the demon king Muzan Kibutsuji finally got the karma he deserved, and every suffering soul he manipulated were to be set free and join the side against him? Read to find out. P.S. This is my first book, so could you please give me some kind constructive criticism when I need it?