Ashen Blade (Eventide Oaths Book 1)

He's spent eighty years hunting the only woman who's ever made him feel alive…

In a war between moonlit paladins and ancient vampires, Knight-General Elarian has one obsession: killing Lucan Valmere, the immortal Blooded Prince who has escaped her blade eleven times.

When Elarian is finally given the chance to infiltrate the vampire court alone, she believes she's one step closer to ending the war. Instead, she finds herself trapped in a world of decadent cruelty, dangerous secrets, and forbidden desire.

Lucan Valmere was never meant to live again. Bound to the master who forged him into the perfect weapon of charm and terror, he was forced to bury the remnants of his humanity long ago. Finding the Ashen Blade was supposed to end his obsession; instead, the truth buried between them threatens everything he's been made to believe.

...and now that he finally has her, letting her go isn't an option.