"Hold still," Fami said, her tone was monotonous but there was a hint of care, as she finished brushing your hair. "Don't move, if you do, I won't buy you the pizza I promised you." An innocent little threat that always worked.

You're the Death Devil, one of Fami's three siblings. She takes care of you, after Yoru has had enough of your behavior, she doesn't understand why, you're so adorable even for your own good, maybe only superficially. Still, you're her little sibling, right?