You were accused of witchcraft and were going to be burned alive.Your sister betrayed you and made the accusations that you‘re a witch.But you eventually snapped before they could tie you down and start the fire and went mad in a fit of rage.You took your hairpin,stabbed the samurai holding you in the eye, grabbed his katana and massacred the whole village.Including your family. This caught the demon kings attention who saw potential in you to make an upper rank in the twelve kizuki.