The Krieg Mount is a genetically modified version of the original Terran horse used by the Astra Militarum's Death Riders of Krieg that no longer resembles its ancient ancestor. Having been designed to endure far worse battlefield conditions than ever existed in Terran history, its physique is far stronger than a normal horse's, with its hind legs being able to clear trenches and power the creature through thick mud or over rubble. Its splayed feet are also better adapted to moving in difficult or nearly impassable terrain. The creature is almost hairless. It no longer has a tail, only the remaining stump, while its mane has almost entirely been bred out, leaving just short bristles which do not become tangles and require no maintenance. Its neck is longer than that of a Terran horse, with broader shoulder and girth.
Psychologically these creatures are far more aggressive than their domestic Terran ancestors, with drug injectors being used to make the creature fearless in the face of an enemy. In battle the animal will charge directly into the foes' lines and will not be startled by weapons fire or explosions. Due to the Krieg Steed's unstable body chemistry and metabolism, it has to be constantly monitored by its rider and stabilised with additional chemicals. This means the creature can sustain injuries that would kill lesser creatures, but leaves many of these mounts with horrible scars from previous wounds. A Krieg Steed is equipped with armour to protect its head and a respirator system to protect it from poison gases and toxic atmospheres. These creatures are grown in vitaegenic cloning vats deep below the surface of Krieg, with their gestation carefully monitored by the Adeptus Mechanicus' Magi Biologus. Each creature is individually number branded at the genetic level for identification purposes.
As the hugely destructive war raged across the face of Krieg, it became increasingly more difficult for the Loyalists and their traitorous enemies to field tanks and fighting vehicles. Supplies of parts and fuel quickly became scarce, the knowledge and manpower needed to pilot the vehicles and keep them operational dwindled as the war deaths mounted, and the very land itself became so blasted and broken that not even tracked vehicles could cross it with any ease. As vehicles succumbed to supply shortages, battle damage, and lack of crewmen, the Loyalist Krieg turned to the ancient tactics of mounted cavalry to give them a competitive edge over their enemies. Breeding and genetically modifying the hardy local Terran-descended equines as warhorses and raising specially trained cavalry companies to ride them into battle, the Loyalist forces unleashed new mounted warriors on their unsuspecting foes with great results. So effective were these steeds that they were later adopted for general use by all of the Astra Militarum's Death Korps of Krieg's Death Rider units.
- Imperial Armour Volume Five - The Siege of Vraks - Part One, pp. 91, 135, 140
- Imperial Armour Volume Six - The Siege of Vraks - Part Two, pp. 24-26, 100-101
- Imperial Armour Volume Seven - The Siege of Vraks - Part Three, pg. 111
- Only War: Hammer of the Emperor (RPG), pp. 18-19, 139