The Living God by Dave Duncan

War had engulfed the whole world. The imposter imperor ruling in Hub was the tool of the paranoid and almighty sorcerer Xinixo, who wielded the combined power of thousands of sorcerer slaves. And yet, despite his seeming omnipotence, the pathetic few who resisted him were still at liberty, even making a little progress. Xinixo'??s prime foe, Rap of Krasnegar, had rallied troll sorcerers to the cause and was about to try enlisting the incomprehensible elves. Fortunately, for his sanity, he did not know that his daughter, Kadie, had been carried off by goblin invaders or that his son, Gath, was heading for stark Nordland to deal with the fearsome jotnar, or that his wife, Inos, was in Guwash, negotiating with gnomes. Shandie, the rightful imperor, was with her, unaware that his wife, Impress Eshiala, believed him dead and had fled with Signifer Ylo, that notorious rake. And none of them knew about the sorcerers of Thume, especially the rebel pixie girl, Thaïle, who chafed against the secret binding of a thousand years. But the odds were still impossible and Longday was fast approaching. The sorcerers of the world foretold blood on Longday.

This book is part of the "A Handful of Men" series.
Here are some other books from this series: