The Prince of Luster and Decay — J.D. Brink

In war, men don't only fight the enemy. Sometimes they must also fight themselves.
 
Sergeant Knox leads the Head Knockers, a unit of scout-saboteurs in the war against the Dread Duke and his armies. They are the favorite squad among Captain Brighton's Stormwalkers, until an ambush kills the Captain, half the company, and Knox's best men.
 
Now the new Captain has new orders.  He's sending the Head Knockers to investigate the possible source of the attack.  The town they find appears empty, but there's something waiting for them there.  And it'll take both heart and steel to defeat it.
 
This stand alone, sword and soldiery novella gives a glimpse into history of the fantasy novel Tarnish.