Book #21 *BBD spinoff*

Start with Dark Lover. Lassiter, the fallen angel, is a little too good at the savior business. In his new role overseeing the fates of all vampires, he's influenced outcomes he shouldn't have, so the Creator is calling him home. But Lassiter has a reason to stay in Caldwell. He's bonded with a female named Rahvyn who seemed to appear from out of nowhere and has powers that defy all reason. Rahvyn understands she doesn't belong in the present-her true place is in the past. Lassiter proves to be undeniable, however, and she lets herself fall for him-until a secret he's been keeping comes to light and she fears that for the angel, it's not about love, but duty. As the Omega's son reestablishes the Lessening Society, and the Brotherhood must resume the deadly war, an unfathomable tragedy occurs. In the aftermath, Rahvyn must decide whether to stay and help--or save herself from an immortal heartbreak she knows will crush her very soul.