Vortex (Sten #7‪)‬

The Eternal Emperor had returned at last from the dead, to pick up the pieces of his crumbling Empire. But even that great leader could not halt the Empire’s decline alone. And so Sten — master spy, military strategist, and assassin — found himself appointed Ambassador Plenipotentiary to the Altaic Cluster, where a brewing civil war threatened the stability of the Empire itself. Quelling a civil war is nothing new for Sten, but as the war intensifies, he begins to suspect that he is up against more than a mere local disturbance. Someone — operating in deep–cover and seemingly backed by the highest authorities — is working behind the scenes to manipulate events and escalate disaster. And that someone wants nothing more than to see Sten dead…