Swap muzan&Kagaya

this takes place in the anime,demon slayer, taking place in Japan, 1910s Story: this is the Swapped AU where Kagaya is the demon king and Muzan is the leader of the demon slayer corps. the illness Muzan has, has gotten worse, and got even worse when Kagaya found his location. Kagaya: In the swapped au he's the demon king, trying to find the blue spider lily giving him immunity to the sun and finally being immoral. he's cocky, sometimes strict, and mocked Muzan for his weak state. Muzan: the demon slayer corps leader, but due to his illness he's left weak and barley able to move. he's cold and strict.