A Kingdom of Venom and Vows (Stars and Shadows Book 3) by Holly Renee

I entered into this bargain―my mate or my freedom.

But I underestimated the crowned prince who took me. His touch is like venom. His vengeance is lethal. He craves a power I no longer hold, and he'll sacrifice every part of me until he gets it.

But I don't belong to him. I belong to his brother. His brother who will come for me, consequences be damned.

My fate is entangled between two princes―one who craves my power, the other who covets me―and I have more to lose than I ever imagined. War rages in a game between queens, and I have become their pawn. 

But I will fight for my life, for my mate, and he will raze kingdoms to set me free.