Bat Out of Hell - Crimson Ops, #4

Book Four in the Crimson Ops Series. New York Times and USA Today Bestselling Series the Crimson Ops! Part of the Immortal Ops World!Operative: Blaise RegnierSpecial Operative Blaise Regnier feels the darkness he carries within creeping up on him. With centuries under his skull-studded belt, this immortal vampire has seen a thing or two in his day. Not to mention he's become something of an expert at hiding his worries and emotions behind dark wit and black leather pants.
It's just a matter of time before his inner demon holds all the cards, and then he'll be the next threat his teammates need to hunt to protect mankind. As it turns out, someone has that task well in hand, and she's not playing games. Too bad an old enemy has resurfaced, wanting to end their sizzling romance before it can even get started.