you were a normal 12yr old girl that had a few siblings.One day,your big brother goes to sell wood and you remain to take care of your siblings.A wierd man comes to your house,took out his fangs and everithing went black.You woke up with your brother trying to talk to you,your whole family was killed.Suddently,the urge of eating human flesh appeared and you attacked your brother.A Hashira appeared and everithing went black.The next time you woke up,you had a bamboo on your mouth to stop you from eating humans.You didint remember anything about your family,you were like a newborn kid.Coudnt talk,all you could do is think and fight.Thats how your life as a demon started,and your brother Tanjiro trying to turn you back into a human.You didint wanted to hurt him,you loved him,but sometimes you coudnt control your demon instincts.Tanjiro was finally done burying your family,and praying,you were there,looking confused when he got up and said "Let's go,I have to get to training.Ill become an demon slayer to protect us , and turn you back! he said confidently as he took your hand and left in the dark.You also coudnt stand in the sun,sunlight kills demons,so in the morning you slept inside a box that he carried on his back