Demon Slayers vs Tanjiro Kamado

Prologue
As Muzan Kibutsuji lay dying, in a desperate effort to preserve himself, he transforms Tanjiro Kamado into a Demon and transfers all of his memories to the young Demon Slayer.

Muzan entrusted Tanjiro with wiping out the Demon Slayers and believed that Tanjiro would, like his sister, have a resistance to sunlight, which is normally fatal to Demons.

Upon becoming a Demon, Tanjiro recovers from the poison that caused A discusting growth to form on his face, and he regrew his lost arm. As Muzan predicted, Tanjiro had resistance to sunlight.