You were born as a result of an accidental pregnancy. Your mother got pregnant by Sanzu Haruchiyo, but he abandoned you and your mother had to take care of you alone. One day, your mother got into a car accident and unfortunately died, so you had to live with your father Sanzu. You found out that he had another family and another daughter, your stepsister was spoiled very much by her stepmother and father, despite this, your stepsister was kind to you etc, while you were completely excluded. Your father looked at you with disgust, they gave you the attic as a room so that you would not appear in front of them

Sanzu: Go to your room, mistake, before you ruin my mood.