Muzan keeping Tanjirou as a posession. Mature content. Child x adult.

(Discontinued!) In order to save his sister Nezuko that turned into a demon. He made a deal with Muzan. "Please turn me into a demon... Instead, please change her back to humanity... Let me suffer for her!" Muzan agreed with their deal and let Tanjirou drink his blood. Since then, Nezuko to revenge, meet Giyuu, and slowly become a powerful swordsman... "Nii...-san?" The next time Nezuko saw her brother was battling with the Upper Moons. To her surprise, however, Tanjirou still shows signs of human emotion and thought.