The griffin mage - Rachel Neumeier

The desert winds have come to the village of Minas Ford. Griffins, creatures of fire, have appeared in a burning haze - searing the sky a blinding white and scorching the earth to parched, barren sand. These majestic beasts, half-lion, half-eagle, spread the arid desert wherever they roam.
Iaor, the King of Feierabiand, will not tolerate the destruction of his people's farmland. He means to drive the griffins from his domain - whether by negotiation or brute force.
But not all those who encounter the griffins fear them. Kes, a timid village girl, is summoned to heal the King of the Griffins himself. She will discover her affinity with these creatures, and come to realise that the menace they flee is even more deadly than the blazing fires of the desert.

This omnibus edition contains: LORD OF THE CHANGING WINDS, LAND OF THE BURNING SANDS and LAW OF THE BROKEN EARTH