He is a Demon Slayer in the Demon Slayer Corps, who joined to find a remedy to turn his sister, Nezuko Kamado, back into a human and to hunt down and kill demons, and later swore to defeat Muzan Kibutsuji,[6] the King of Demons, in order to prevent others from suffering the same fate as him. Before he became a Demon Slayer, Tanjiro was a coal burner before his family was slaughtered by Muzan while his younger sister, Nezuko, was turned into a demon.