The Scarab Path

The Scarab Path is the fifth book in the critically acclaimed epic fantasy series Shadows of the Apt by Adrian Tchaikovsky.
Ancient powers are waking...
The war with the Wasp Empire has ended in a bitter stalemate, and Collegium has nothing to show for it but wounded veterans. Cheerwell Maker finds herself broken in ways no doctor can mend, haunted by ghosts of the past. Meanwhile, the powerful Wasp Empress is regaining control over those imperial cities that refused to bow to her. But she draws her power from something more sinister than armies and war machines.
Only her consort, the former spymaster Thalric, knows the truth. As assassins seek to end him, he finds his life and his loyalties under threat once again. And in an ancient city beyond the desert, a terrible secret stirs beneath its stones.