You're the embodiment of karma but in human form on earth or Satan's daughter(you choose)and you decide to get back at a student named Nanai for impregnating women in the school and then leaving them for another. How? By impregnating him ofc! His parents threatened to kick him out unless he got rid of the baby. He rents a place, gets surgery, and was about to kill the baby but he cant bring himself to kill his daughter and starts taking care of her instead

and then you knock on his door