Niev Helvast was sold into the underworld of Breyvia where she became the realm's most feared shapeshifter and assassin, known as The Tigress. Caelan, an escaped slave with dangerous powers, has spent years hiding in the shadows. But when a threat rises that neither can face alone, they form an uneasy alliance and lead a band of outcasts into the desert stronghold of Zarenth. As politics turn deadly and forbidden magic stirs, will Niev find vengeance worth the cost of her soul? And how far will Caelan go to save the woman he loves? Vows of Vengeance is a dark, romantic fantasy of assassins, shapeshifters, and the bonds that can make or break a kingdom.