Beyond the Treaty by A.L. Robinson

In the war-scarred world of Mythrendel, peace is a brittle illusion. One preserved by a centuries-old pact between three rulers: the Vampire Lord Kaelen of Ebonshade Keep, the Demon Prince Azrael of Obsidia, and the enigmatic winged Queen Elara of Lunairis. For generations, their realms have stood in a tense truce, their powers balanced by an uneasy alliance known only as The Treaty.
But when Elara uncovers hidden truths about the magical bond she is forced to undergo, a ritual intended to secure peace but woven with betrayal. She is thrust into a shadowy war for the soul of the realm. With whispers of ancient curse, forbidden magic, and a Council intent on control, Elara must navigate political deceit, unravel buried legacies, and confront a destiny far darker than she ever imagined.
As tensions flare and kingdoms prepare for war, Elara finds herself torn between duty and desire, between the cold calculation of Kaelen and the reckless fire of Azrael. With allies both immortal and mortal, she must choose who to trust and who to betray.

Because peace was never meant to last.