The Imperial Guard is the main fighting force of the Imperium of Man. It consists of human soldiers (with the exclusion of the occasional abhuman) without any extraordinary abilities or hyper-advanced technology. With the Imperium of Man controlling around one million planets, the amount of soldiers available to the Imperial Guard is practically unlimited. In fact, it has more fighting men than some alien species have population; even the Departmento Munitorium itself does not know the exact number. Millions of guardsmen are raised, shipped out, deployed and die every day in a hundred wars on a thousand worlds.
With the immense number of troops available to the Guard, their fighting power tends to add up and may crush the strongest of foes. The Guardsmen can simply overwhelm the enemy – if it fails, they can get more men and attack again. It is said that if the Space Marines, who, in contrast, are fewer than Imperial planets, are the Imperium's scalpel, then the Imperial Guard is the hammer.
The origins of the Imperial Guard go back to the Great Crusade, the 200-year expansion war in the 30th millennium when the Emperor of Man was reuniting mankind. Although the Emperor had his early Space Marine Legions to spearhead his invasion, the Astartes had not the numbers to claim and hold it all. Thus a larger force was needed to garrison conquered worlds, build massive sieges, and the like. This force was called the Imperial Army.
The earliest precursor of the Guard was formed on Terra itself during the homeworld's Unification Wars by preserving some of the older military units (even though battlefields were dominated by early Space Marines). When new worlds were conquered, troops would be recruited from the population of each world; originally for defending against other invaders and to prevent rebellions. However, when the Imperium expanded, these armies were soon needed on the front as well. This was the founding of the Imperial Army, at that time placed under the command of the Space Marine Legions.
When the Horus Heresy struck and nine Space Marine Legions turned traitor, some of the Imperial Army units continued following orders from the Traitor Legions, turning on the loyalist army in civil war. Some ambitious commanders ignored the conflict altogether and set out to build their private empires.
After the civil war and the retreat of the Traitor Legions – along with a number of Traitor Regiments – the Imperial Army was reorganized, much like the Space Marine Legions. Steps were taken to decrease the power of individual officers in case of future traitors. The navy was separated from the army, so that army officers could no longer command transportation for ground troops. Thus two new forces were created; the Imperial Guard and the Imperial Navy.
Excluding the lack of an integrated naval force, the Imperial Guard works much the same way as the old Imperial Army. Troops are still recruited from Imperial worlds and either assigned in the Planetary Defence Force or sent wherever needed.
Imperial Guard troops are organized into largely autonomous Regiments. These are composed of troops recruited at the same time from the same world, commanded by their own officers and supported by their own non-combat personnel. Once a Regiment is formed and sent away, it is usually not reinforced. If it takes many casualties, it may be merged with another crippled Regiment, or it may be completely destroyed. Either way, Regiments are not intended to be permanent; once one is used up, the Imperium can always create more.
There is no standard template for an Imperial Guard Regiment. As the population level, industrial capacity, military tradition and other factors make each world unique, so are their Regiments. There is variance in the size, equipment, training and command structure. A densely populated jungle world will naturally produce a different kind of army than a sparsely populated ice world.
Although there is variance, the Regiment is usually commanded by a Colonel. Majors, Captains and Lieutenants act as intermediary officers while Sergeants lead combat squads. A battlegroup formed of several Regiments is commanded by a General. From here, it is a complex path with many steps up to the highest level of command: the Departmento Munitorum, which is led by three of the High Lords of Terra – the Chancellor of the Estate Imperium, the Master of the Administratum and the Lord Commander Militant of the Imperial Guard.
- Cadian 412th (Dawn of War: Winter Assault)
- 1st Kronus (Dawn of War: Dark Crusade)
- 252nd Kauravan Conservator (Dawn of War: Soulstorm)
- 85th Vendoland (Dawn of War II, Dawn of War II: Chaos Rising)
- House Vandis (Dawn of War II: Chaos Rising)