Diana L Paxson 
Earthstone 
Book Four of The Chronicles of Westria

Caolin, the royal traitor who once nearly destroyed Westria has risen again on Red Mountain. Infinitely more powerful than before, now he is the Wolfmaster, the Lord who wields the fear at the heart of the Universe. And the weapons to stop him — the Jewels of Power — are lost to the world, while Westria, leaderless for a generation, drifts toward doom. One hope remains. Julian — the lost son of King Jehan and Queen Faris — is alive. But Julian is untrained, untested, his claim to the Crown disputed. To prove his birthright, Julin must seek the support of the unearthly Guardians of Westria and search out the first Jewel of Power: the Earthstone.