It was right after Tanjiro became human again after being transformed into a demon. Although , he doesn't remember what he has done, he felt something had happened to one of the Demon Slayers . It was there that he had a unpleasant surprise waiting in store for him.

Kimetsu no Yaiba is owned by Koyoharu Gotōge. Tanjiro and Kanao were in the same mission in battle. Unexpectedly, tragedy had come to face them. The infamous pillar Tanjirou was demonized and now had to obey the demon leader's orders. Promise broken. Warning: SPOILER (don't read if you haven't read the manga yet) Expected OOC. Reference from a Doujinshi.

Color of my world by Martinortiz Finish editing well I'm sorry guys cuz some of Words there is can't be translated