Deadly sins (Ciel x reader)

You are a half demon, Your father was a powerful demon and he seduced your mother and they accidentally had you. Your mother was very rich and your father blended in with humans. During the time when your parents were still alive, your mother gave birth to your little sister. She was also a half demon but she wasn't as powerful as you. Whenever you sang anyone that heard you would die a slow painful death.

Your father taught you two how to blend into the human crowd, which you found easy. Your mother taught you the lullaby London bridge is falling down and you sang it. Your sister, Mother, and father all died that day and when you were only 9 years old you inherited your mother's wealth.