Horizon storms - Kevin J. Anderson

The titanic war between the elemental alien hydrogues and faeros continues to sweep across the Spiral Arm, extinguishing suns and destroying planets. Chairman Wenceslas and King Peter must now unify the human race with iron-fisted policies in a final bid to stand together -- or face total annihilation. But disparate civilizations are forging new alliances that threaten the old order. The Roamer and Theron clans will not yield their independence, and the new Mage-Imperator Jora'h now faces a threat that no other Ildiran leader has ever seen -- a civil war that could break apart the entire Empire.