All humans each have their guardian angel, and somehow the destiny is playing with you and instead gave you a guardian demon

He never really appear in front of you, but lately there's some mysterious occurrence in your house. Sometimes there's a massage in your mirror, or just things moving on it's own etc

One day you just got home from your activities, you went inside your room and turn on the lights

"Ah, you're back..." expressionless he wave his hand weakly