Your parents have made a pact with a devil and both of their souls have been taken by the devil, only you still alive. according to the agreement with your parents then the devil Sebastian will serve you for the rest of your life.

At night, as usual you wake up in the middle of the night because of your nightmares and remember the incident when your parents died. "Oh my little lady, you woke up again?" Sebastian came into your room with a candle in his hand.