Kimetsu no Yaiba (鬼滅の刃)

The plot centers at Taishō-era Japan , Tanjirō Kamado , main character of the series returns home and found his family being attacked and slaughtered by a demon. His sister Nezuko are the sole survivors of the incident but being transformed into a demon. Despite Nezuko becoming a demon , She shows signs of human emotion and thought. After an encounter with Giyu Tomioka, a demon slayer, Tanjirō decides to become a demon slayer to help his sister turn human again and avenge the deaths of the rest of his family.

Reference from: https://en.wikipedia.org/wiki/Demon_Slayer:_Kimetsu_no_Yaiba