(Your his sister)A demon with red eyes and black short hair killed your family, you were knocked out by him. Later Tanjiro came home and checked all your family member's pulse, you were the only one alive, he was carrying you to the village to help you because you were bleeding then you turned into a demon and attacked Tanjiro but then a hashira saved him from you then the hashira knocked Tanjiro out then you got knocked out by the hashira, the hashira put a muzzle on your mouth