Mindgod - The Mindguard Saga, #4

The war humanity has dreaded since the dawn of telepathy. An enemy beyond the scope of human understanding. Veyko has broken free of his conditioning. Once the Enforcement Unit's deadliest assassin, the genetically engineered New Mindguard has turned against his creators. Now he is determined to put an end to his enslavement. After developing a hybrid form of telepathy that bridges biological and artificial cognition, he goes on a killing spree and escapes the Federation in humanity's most advanced neuroreceptive spacecraft.
His destination: the Shared Mind's home world. Intent on taking over the mind of every sentient being, Veyko must first conquer the only telepathic civilization in the known universe and use its collective consciousness to fuel the next stage of his evolution. When the Shared Mind becomes nothing more than a weapon wielded by a vengeful god, the fate of the world once again rests in Tamisa Faber's hands. But Tamisa is in no condition to fight.
Disgraced, disfigured and hiding in the Hando Desert, the former High Commander must turn to allies and enemies alike if she has any hope of saving humanity from a fate worse than death.