Echoes of Empire, book 1: The Garden of StonesMark T. Barnes2013

An uneasy peace has existed since the fall of the Awakened Empire centuries ago. Now the hybrid Avān share the land with the people they once conquered: the star-born humans; the spectral, undead Nomads; and what remains of the Elemental Masters.
With the Empress-in-Shadows an estranged ghost, it is the ancient dynasties of the Great Houses and the Hundred Families that rule. But now civil war threatens to draw all of Shrīan into a vicious struggle sparked by one man's lust for power, and his drive to cheat death.
Visions have foretold that Corajidin, dying ruler of House Erebus, will not only survive, but rise to rule his people. The wily nobleman seeks to make his destiny certain - by plundering the ruins of his civilization's past for the arcane science needed to ensure his survival, and by mercilessly eliminating his rivals. But mercenary warrior-mage Indris, scion of the rival House Näsarat, stands most powerfully in the usurper's bloody path. For it is Indris who reluctantly accepts the task of finding a missing man, the only one able to steer the teetering nation towards peace.