Warborn

A run-in with an enemy who does not play by the usual rules leaves Thorn stranded in the Abyssal Lands. The Herald of Terminus is out there, working toward an ending that takes everything with it, and a plague sits waiting for someone to let it loose.

The only route close enough to do anything about either runs through the Blood Legion, an elite military order Thorn had thought he understood. Getting inside it teaches him how little of that was accurate, and the answer he needs is not one anyone has tried before.

Book nine of Seth Ring's Tower series, set in the world of Nova Terra.