Imperialis Militia
The Imperialis Militia, also known as the Imperial Militia, was a large auxiliary and reserve branch of the Imperial Army during the Great Crusade and Horus Heresy. The Imperialis Militia was analogous to the Planetary Defence Forces of the 41st Millennium.[1c]
Overview
The first units of the Imperialis Militia were formed during the Unification Wars by the Emperor, where they comprised of normal Human auxiliary units who fought alongside the early Imperial Army and Thunder Warriors. By the time of the Great Crusade, the Imperialis Militia was tasked with occupying and garrisoning worlds brought into the early Imperium. Militia units would be deployed on newly pacified worlds as the Expeditionary Fleets of the Great Crusade moved on to their next conquest.[1c]
Much like the PDFs of M41, the Imperialis Militia was not a galaxy-spanning military force. Rather, its makeup varied greatly world to world and was led by a variety of local Imperial Commanders, Officers, administrators, and even tribal kings. However it was very common for Militia units to consist of a core of professional soldiers which in times of war would be greatly augmented by a force of reserves and conscripts. Also similar to the PDFs of the 41st Millennium, the Militia tended to be a more lightly equipped and poorly trained force when compared to regular Army units, Solar Auxilia, or the Space Marines.[1c]
During the Horus Heresy, the Imperialis Militia fell into internal strife along loyalist and traitor lines, as was typical with nearly every other organisation within the Imperium at the time.[1c] They were often used as cannon fodder during the civil war by both sides, though in particularly by the Traitor Legions.[5]
Forces
Infantry
- Force Commander - Commanding officer that may be a Governor, General, noble, clan chieftain, etc. The nature varies depending on context and the world's own nature.[6]
- Discipline Master - Similar in role to a modern Commissar, they were recruited from hand-picked Veterans[1d]
- Medicae[6]
- Enginseer Auxilia[1d]
- Command Troop - Consists of a Lieutenant, Bodyguard, and Grenadier bodyguards. Some may be mounted.[6]
- Rogue Psyker - Used by traitor Militia forces aligned with Warmaster Horus.[6]
- Grenadier Troop- The most capable infantry units with the best training and equipment.[6]
- Beastmaster Troop - Drawn from more primitive worlds, these specialists were capable of capturing and taming dangerous local wildlife and turning it against their foes.[6]
- Infantry Troop - Standard troop formation equipped most commonly with Lasguns or Autoguns, though in some cases on more primitive worlds Muskets and even Bows may have been used.[6]
- Levy Troop - Conscripts quickly pressed into service in times of crisis with little to no training and only basic weapons.[6]
- Fire Support Troop - Heavy weapons squads equipped with Heavy Stubbers, Mortars, Multi-Lasers, Heavy Bolters, Heavy Flamers, Missile Launchers, Autocannons, or Lascannons.[6]
- Reconnaissance Troop - Scout units equipped with Shotguns and Longrifles.[6]
- Voidjumpers - Reconaissance Squads equipped with Jump packs, similar (and possibly predecessors) to the modern Imperial Guard Assault Squads[4]
- Cavalry Troop - Light vehicle units deployed for scouting or rapid strike. Most commonly equipped with Bikes.[6]
- Imperial Provosts - Mixture of security units from Arbites, Enforcers, retired Army troops, Tithe collectors, and Hive Gang enforcers.
- Penal Units[6]
- Ogryn Troop[6]
- Kinfolk Helots - Inducted Squats[6]
- Beastmen Levy[6]
For Forge Worlds, additional Militia units may be raised from local Tech-Thralls or industrial workers. For those traitorous worlds pledged to Horus, all sorts of debased Cultists and Mutants may have been included in these forces.[6]
Field Artillery
- Field Guns - The primary source of heavy firepower, consisting of either Kalliope Rocket Mortars, Heavy Lascannons, or Thunderblast Battlecannons.
- Rapier[6]
- Heavy Ordnance Battery - Heavy field artillery units equipped with Heavy Mortars, Heavy Rocket Bombards, Siege Cannons, Medusa Mortars, or Heavy Quad-Launchers.[6]
Vehicles
- Sentinels[6]
- All-Terrain Patrol Vehicles[6]
- Scout Rovers[6]
- Gorgons[6]
- Leman Russ Battle Tanks[6]
- Malcador Heavy Tanks[6]
- Basilisks[1c]
- Medusas[1c]
- Utility Haulers[6]
- Industrial Rigs[6]
- Baneblades[6]
Aircraft
Equipment
The Imperialis Militia often used equipment very similar to the Imperial Guard of the 41st Millennium. Individual armaments were highly unstandardized and often locally provided, resulting in infantry going into battle with anything from Lasrifles, Lascarbines, and Bolters to black powder muskets and crossbows. Overall however, there was no standardized equipment for the these militia forces and the quality of what they had available varied considerably planet to planet.[5]
Known Imperialis Militia Units
- Calth Irregulars[7]
- Erud Provincial Militia[1a]
- 199th Thorion Yeomanry - Turned Traitor and fought the Ultramarines at the Battle of Calth.[1b]
- Secundus Levy - From the domains of Irriane Vail of Beta-Garmon II
Sources
- 1: The Horus Heresy Book Five - Tempest:
- 2: Legions Imperialis: The Great Slaughter, pgs. 10-13
- 3: Warhammer 40,000 Compendium, pgs. 41 & 44 — Rough Riders and Whiteshields
- 4: Legacies of the Age of Darkness: Imperialis Militia
- 5: Horus Heresy: Age of Darkness 3rd Edition Rulebook, pg. 27
- 6: Warhammer Community: Imperialis Militia – Download this free PDF army list - Legacies of the Age of Darkness: The Imperialis Militia PDF (Saved archive page, dated 28 August 2025, last accessed 28 August 2025, original link: https://www.warhammer-community.com/en-gb/articles/z9ikifym/imperialis-militia-download-this-free-pdf-army-list/)
- 6a: p. 24
- 7: The Horus Heresy: Legions