Wrath of the Gods

Wrath of the Gods is the eighth book in the epic 'Nexus' series, part of the growing Star Crusades universe that chronicles humanity's first steps away from Alpha Centauri and beyond.
The opening battles of the bloodiest war in human history have been fought, and now the enemy spreads from world to world, exterminating all before them. This is no war for territory or resources, it is one of genocide. The valiant efforts of the Alliance, Helions, and Khreenk make the Biomechs pay a terrible price, yet still they continue onwards. Each of these massive assaults is being conducted from deep inside their fortified Arks, the command centers of the Biomech campaign. These vast behemoths combine the capabilities and firepower of battleships with the size and resources of entire space stations.
With trouble brewing between the Anicinàbe and Byotai, there are few remaining allies to counter this bloodthirsty invasion. Two more Biomech fleets make their way to the planets of Micaya and Libuscha, and the remnants of the assault force around Eos turn their attention on the dormant Black Rift. It falls to the heroes of the Great Uprising to rally forces from Mars to Hades to meet this challenge. Admiral Anderson and General Rivers assemble every combat unit they can find to fight the war. At the same time, Spartan and Teresa Morato solicit the aid of an ancient race, one that has even greater reason to bring down their old foe. Together they hope to assemble a mighty host in T'Karan, one that can unleash a counterattack and eradicate the enemy once and for all.
The 9-book Star Crusades Nexus series includes:

Legions of Orion (Star Crusades Nexus, Book 1)
Machine Gods (Star Crusades Nexus, Book 2)
Heroes of Helios (Star Crusades Nexus, Book 3)
The Great Betrayal (Star Crusades Nexus, Book 4)
Prophecy of Fire (Star Crusades Nexus, Book 5)
Call to Arms (Star Crusades Nexus, Book 6)
Battle for Helios (Star Crusades Nexus, Book 7)
Wrath of the Gods (Star Crusades Nexus, Book 8)
The Black Rift (Star Crusades Nexus, Book 9)