The Fall of the Flame Prince. The Fifth Kingdom, #4

Book 4: The Fall of the Flame PrinceBy Brinda PhokeerdassIgnar burns. The Ashborn rise. And at the heart of the fire stands Prince Talren-once Kael's friend, now the self-proclaimed Flame Sovereign. The elemental realms spiral into chaos as Talren seizes the Fifth Element for himself, wielding its corrupted power to bend armies and scorch opposition. Kael, believed dead, emerges from the shadows, carrying the weight of defeat and a fractured power barely holding him together.
But the world no longer waits for heroes. As Kael races to stop a war he may have sparked, he must decide who he can save-and who he's willing to sacrifice. Because in the kingdom of fire, loyalty is tested in ash, and the line between savior and destroyer burns thin.