Empire of light - Gary Gibson

The nova war has begun to spread as the Emissaries wage a fierce and reckless campaign, encroaching on the area of space occupied by humanity and forcing the Shoal into a desperate retreat. While Dakota goes in search of the entity responsible for creating the Maker caches, Corso, left in charge of a fleet of human-piloted Magi ships, finds his authority crumbling in the face of assassination attempts and politically-motivated sabotage.

If any hope exists at all, it lies in an abandoned asteroid a thousand light-years beyond the Consortium's borders, and with Ty Whitecloud, the only man alive with the skill to decipher the messages left behind by an ancient race of star travellers. Unfortunately Whitecloud is locked in a prison cell aboard a dying coreship adrift in space, awaiting execution for war crimes against Corso's own people. But if humanity has any hope of survival, Corso is going to have to find some way to keep him alive - and that's only if Dakota doesn't kill him first ...