Wicked Heat. Lick of Fire Series, #1

Four haunted men, and a death wish with my name all over it. My friends call me Sephy (short for Persephone). At seven I killed my first demon. It wasn't much, an accident really... but one taste of a demon kill and I was possessed. At thirteen, my home-town banished me. Still, I considered this ability a gift and not a curse, until my twenty-first birthday... when all Hell broke loose. Demonic spirits are crossing over into our world, promising terrifying things.
They're targeting me and my piece of shit ex-boyfriend, a damn cop who's been riding my case for the last two months, a friend who's broken my heart, and a brother of a girl I saved from a demon attack. Normally, I'm a look-on-the-bright-side kinda girl, but the bright side is getting darker, and demons are closing in. And the only hope of me surviving is to team up with these four guys, as long as the madness doesn't claim me first.