David Farland 
Brotherhood Of The Wolf 
Book 2 of the Runelords

The epic struggle begun in THE SUM OF ALL MEN continues in BROTHERHOOD OF THE WOLF. Gaborn has managed to drive off Raj Ahten, but Ahten is far from defeated. Striking at far-flung cities and fortresses and killing dedicates, Ahten seeks to draw out the Earth King from his seat of power, in order to crush him. But as they weaken each other’s forces in battle, the armies of an ancient and implacable enemy issue forth from the very bowels of the Earth. . .