The Horde Wars: Ravenous (Book 1)

In a small Southern town where everyone knows everybody else's business, Cady Swann has managed to keep a few secrets to herself...among them, the fact that every night for the past fifteen years she's been protecting the town probably the world from a monstrous invasion of nether-worldly beasts. Unfortunately for Cady, someone has discovered her secret. Someone or something not quite human.
Obsidian is a warrior, proud and fierce. He wants Cady to join his army in the war against their common foe. He also wants her to join him in his bed, to tempt and delight her into tying her life to his and leaving her world behind...forever.