Kimetsu no Yaiba Novelize

As long as anyone can remember, there have been rumors of man-eating demons living in the woods. Even in the more enlightened Taishou era, the townspeople never go near there at night. Tanjirou Kamado, a kind boy who has been supporting his family as a coal seller since his father died, quickly learns that the local superstition is more than just rumors when he returns home one day to find his family slaughtered by demons. Only he and his sister Nezuko manage to survive, but she is transformed into a demon. Determined and resolute, he is recruited into the Demon Slayer Corps and his quest to help turn his sister human again and avenge his family's deaths begins.

(Source: Shueisha, translated)