The Light at Last - The Last Prince, #3

Winning the throne was hard. Keeping it may be impossible ... Across the sea, an unspeakable evil rises out of myth, bent on conquest and destruction. Each kingdom that falls before it brings it one step closer to Eyrdon. And there is only one way to fight it: with magic. How can Wardin hope to defend his own land from such a threat, while magic is still outlawed across his borders? Desperate to save his people at any cost, he'll weather brutal betrayals, heartbreaking losses, and even dubious divine intervention.
But as time grows ever shorter, none of it will be enough. If he is to keep anything he holds dear, Wardin must find a way to make an ally of his mortal enemy-and bring magic back to Cairdarin once and for all.