Breath of Heaven

The Autumn Tree has fallen, the protection it provided the human, dwarren, and Alvritshai races destroyed.  Now the Wraith army is marching to war, laying siege to the human Provinces and harassing the dwarren clans on the plains.  Colin has dealt Walter a significant blow, but he has failed to halt the activation of the Source—the one Well that controls all of the others—and he has sustained a grievous wound in the process.  As the Wraith armies wreak havoc across Wrath Suvane, Colin realizes there is only one way to stop them:  He must return to the Source and give himself completely to the Lifeblood, a taint he has fought since he first drank from the Well lifetimes ago.  Only then will he be able to stop Walter and the Wraiths from destroying Wrath Suvane.  . . .  

All it will require is the sacrifice of his humanity.