The Solar Auxilia was an elite fighting force within the Imperialis Auxilia during the Great Crusade and Horus Heresy originating from the Segmentum Solar. Of the myriad regiments and battalions of the Imperialis Auxilia (known in Low Gothic as the Imperial Army) the Solar Auxilia were amongst the most elite, disciplined and well-equipped fighting forces, widely considered by many second only to the superhuman Legiones Astartes in their military effectiveness in battle. Solar Auxilia soldiers were not only trained as infantrymen but also for space combat, combat engineering, planetary exploration, and Death World survival missions.
By the second century of the Great Crusade, the Solar Auxilia made up between 20-25% of the Imperial Army.
Originating from the Sol System from human drawn from Terra and Saturn, these troops were the best organized and equipped Imperial Army forces. Their doctrine emphasized discipline, coherence, aggressive defense, and concentrated firepower, making them highly effective soldiers. As the Great Crusade ground on, the Sol System could no longer provide enough manpower for the much-demanded Solar Auxilia forces, so recruits were drawn from elsewhere.
The base operating unit of the Solar Auxilia on the strategic level was the Regiment, comprising about 5,300 soldiers and staff. However as the Great Crusade expanded in size, much larger Solar Cohorts were established of 120,000 personnel under the command of a Marshal Solar. These would be broken into a number of sub-cohorts, each with a nominal strength of 1,200 under a Legate Commander, Commander, or Sub-Commander depending on its particular type.
On the tactical level, the building block of the Solar Cohort was a Terico, itself made up of three sections whose nature was defined by their weaponry and battlefield role. The most commonly deployed Terico formation consisted of three sections each comprising 20 armored Lasrifle-equipped troops. Veteran Veletaris Tericos usually consisted of three squads of ten veteran troops equipped with more advanced short-range weaponry such as the Volkite Charger or Flamer. Fire Support Tericos commanded three batteries of crew-served weapons platforms, most commonly the Rapier.
The most iconic piece of the Solar Auxilia was its Solar Pattern Void Armour, a carapace-reinforced full environmental combat body suit with fully integrated life support units. The most commonly issued weapon was the Kalibrav V-1 pattern Lasrifle, a higher-quality Laser firearm superior to a standard Lasgun. Support weapons included Flamers, Volkite Weapons, Plasma Weapons, Rotor Cannons, and Meltaguns. The Solar Auxilia also had its own units of Ogryn Charonites for infantry support.
The Solar Auxilia made use of a wide array of heavy vehicles, most notably the Dracosan Armoured Transport and Aurox. The Arvus Lighter was most frequently used for airborne landing operations. The most common heavy support vehicles were the Leman Russ Battle Tank, Malcador Heavy Battle Tank, Basilisk, Valdor, Malcador, and a variety of Super Heavy Tanks that included the Baneblade, Stormhammer, Stormblade, Stormsword, and Shadowsword.
- 1522nd Solar Auxilia Cohort from Agathon
- 204th Solar Auxilia Cohort from the Manachean Commonwealth, they took part in the Bardall Prosecution.
- 142nd Solar Auxilia Cohort from Cthonia
- 1: Forge World
- 2: The Horus Heresy Book Four - Conquest, pgs. 80–95
- 3: Warhammer: Visions 20, pg. 47 — Forge World
- 4: Forge World