Eternity's Mind

Eternity's Mind, the climactic final volume in Kevin J. Anderson's Hugo-nominated Saga of Shadows trilogy.
The desperate war with the Shana Rei seems lost. All across the transportal network, space is tearing apart, the links between the gateways are breaking down, the fabric of space unraveling, and entire sections of the Spiral Arm are becoming galactic dead zones.
The Shana Rei have infiltrated the transportal network, and desperate populations have to cut themselves off, shutting down their portals, often their only connection with the rest of the Spiral Arm.
In desperation, humans and Ildirans turn to the most unlikely allies, the unpredictable faeros.