Demon Slayer: Kimetsu no Yaiba
Available on iTunes, Crunchyroll
Tanjiro, a kindhearted boy who sells charcoal for a living, finds his family slaughtered by a demon. His younger sister Nezuko, the sole survivor, has been transformed into a demon herself. Tanjiro resolves to become a demon slayer so that he can turn his sister back into a human, and kill the demon that massacred his family.