The Saints of the Sword. Book Three of Tyrants and Kings

John Marco presents the riveting conclusion to his sweeping fantasy saga - in which three unlikely allies stand united against a terrifying crisis that threatens to devastate a world. Biagio, Emperor of Nar, was once a madman and a tyrant. Now he wants peace. The irony is that no one believes him. Instead, the cruelest of his minions are amassing an army to usurp his throne, bringing a new scourge to a battle-scarred world.
But the wily Biagio has one more desperate plan. Alazrian Leth, bastard son of Aramoor's governor, is barely sixteen, but this young prince secretly possesses rare magical talents. Biagio sends Alazrian on a near-impossible mission: to convince outlawed priest Jahl Rob and his followers - the fearless Saints of the Sword - to search for the exiled ruler of Aramoor and the mysterious people called the Triin.
If these ancient enemies can unite into one great army, a boy's strange and wonderful magic may be the spark to heal a wounded world ... or set in motion an unimaginable betrayal.