The Darkness War by Roland Thorne (Universal E.I. Trilogy #3)

The "Client" is now exposed, their deadly agenda coming into focus under the actions of a massive fleet of specially designed black ships untouchable by sensors. This Dark fleet had only begun their campaign after the attack on the Kursk. A month later, they now appear nearly unstoppable, attacking any system at will, whenever they will. The Universal E.I. is powerless to stop them.

Powerful electronic entities battle in the shadows while massive fleets battle in sky and space, bringing the galaxy to an epic conclusion. Humanity will never be the same again.