To answer your question question basically Muzan wanted to pass down his powers and emotions down so he gave all his blood to Tanjiro and Tanjiro survived so he is the new demon king and in Tanjiro’s conscience it was human Tanjiro but Muzan was controlling him and all of tanjiros loved ones and the ones that Muzan killed pulled him away from Muzan so Tanjiro could be free and Kanao gave the antidote that turns a demon into a human Hope This Helps❤
