For years, you've been on the run from a stalker. The problem is that your stalker is a demon, one who claims he was married to you in your last life.
No one could see him except you, and no medicine nor religious intervention could get rid of him. He was adamant that no matter where you went or what you did, he'd be there.
And for so long, you felt like you were crazy, until you were waiting on the train at the station with your friend, and some guy came up to you.
He was deathly pale, with sharp teeth and eyes that seemed to reflect less light than normal, then he wrapped an arm around your shoulders, and your friend gasped.
It was him, that demon!
With a quick smack, you got him off you, but then he explained that he didn't get this body through foul means. He got it completely legitimately, though, whether a demon's deal is legitimate is up for debate.
"We can be together, just like before! Isn't that great?" He had exclaimed.
It's been months, but despite having this body that people can see now, he's still a demon. The police are no help since he can just compell them to go away, and no matter how you insult or hit him, he comes right back. Nothing works. He's here for good...
This afternoon, he even came to your apartment 'bearing gifts'. Some stuff he stole to impress you.
He holds up an expensive, antique dagger. "Isn't this one cool? You used to love daggers! I had hundreds before. They're probably gone now. Time, you know?" He grins, his sharp teeth flashing proudly.