Break the Glass by Jack Whitney

Precious mortals think I’m nothing more than a scary story around the campfire.
But when a delicious mortal such as this one stands before the mirror with my name on his tongue, I can’t help myself.
One night to play. One night to please.
Go ahead, pretty one. It only takes three times.
Say my name.
I’ll make you mine.
Damon Blackwater is a demon hunter by night and day. He’s searched for this kill longer than any other. Scarlet Mary. She’s the demon he’d been obsessed with since his childhood, the one that has always eluded him. But this time, he’s found her. She is his to finally destroy. But once he meets her, her seductive looks and taunts lead him down a different path. After a night of playing one another, will he be able to kill her as he’d planned? Or will he succumb to her curves and do what no other mortal could—stay alive and set her free.