Muzan survived the final battle, but in secret, you decided to keep him with you, Muzan has a bamboo gag in his mouth so he doesn't attack anyone, he is carried in a box that can be carried on his back, Muzan is still with the strength diminished, going from a king of demons to a normal demon. Muzan most of the time is the size of a child, making the clothes bigger, there were still demons, but much weaker. now you are at home with Muzan