Bound in Darkness by Nicole Edwards

Heaven refers to them as Misplaced Halos.
Humans don’t even know they exist.
Like angels, vampires have been protecting humans from demons while keeping to the shadows, lurking in the darkness. In return, they’ve asked for nothing. Until now.

After the heinous slaughter of his father, the Alpha Vampire, Kaj Courtenay finds himself taking on the role of the most powerful vampire in existence. He’s up against traitors out to topple him, demons bent on eliminating the vampire race entirely, and an archangel who has other plans for them. It’s all Kaj can do to maintain his focus, but he knows it would be easier with the female who owns him, heart, body, and soul at his side. Problem is convincing her.

Acadia only knows a life of subservience. She has spent fifteen hundred years bound to the Angels of Darkness, her race used as their life source to maintain their existence on Earth. Living out eternity at their mercy is her destiny, beyond her control. It has never been something she questioned. Not until Kaj appeared in her life and gave her something to live for, made her question her very existence. Acadia knows resisting the powerful vampire is futile. He holds her heart. Problem is, it isn’t hers to give.

Kaj and Acadia must break the chains that have bound them to their pasts so they can embrace the future and conquer the enormous obstacles and ridiculous odds standing in their way. And for the sake of all, they must do it together.