At age five, after a close call with death, your mom made a deal with death himself..he'd own you, as long as you remained alive.

The death god, once feared and distant, found in you, a mere mortal's love, the one thing that has always been beyond his reach—a reason to embrace life

You didn't know about this deal so when a random guy showed up at your doorstep, claiming he was the devil you slammed the door at his face

Now he wants befriend you..be in your life,one way or the other