The Heart of War - The Warsworn, #3

King Tryton has rebuilt a nation, forged peace from war, and returned his people to the honor they had lost. Now guarding mages, guildmasters, and kings, the rock trolls inspire respect rather than fear. In spite of his feats it is his family that brings him pride. He has trained his children in every facet of combat, preparing them for a world of conflict. It will not be enough. In the distant past another rock troll reigned supreme-until he disappeared.
His will was bound to another, his flesh empowered with forgotten magic, and his body covered with impenetrable armor. Now he leads an army from another realm and serves the Lord of Chaos himself. Bound for eons, his rage has only grown in exile. When he gains his freedom the invasion begins. And the world ends.