Tanjiro Kamado is a kindhearted and intelligent boy who lives with his family, making money by selling charcoal. Everything changes when his family is attacked and slaughtered by demons (oni). Tanjiro and his sister Nezuko are the sole survivors of the incident. Nezuko is now a demon, but still surprisingly shows signs of human emotion and thought. Tanjiro becomes a demon slayer to help his sister turn human again and to avenge the loss of his family.