 Despite its vast, almost incalculable size, the Imperial Army could not, in every case, be relied upon to be able to provide the right soldiers for the right task. This was simply a factor of both its role and its form. The might of the Exertus Imperialis existed for one reason, the demand for manpower. The galaxy is, as has been said, a very, very large place, and the Legionnaires Astartes, though mighty, are but few in the face of the sheer size of the galactic volume. The Imperium, however, did and does not lack for unaugmented humans, and while most of the hordes of humanity could never become Astartes, they could still fight and they could still conquer. The Imperial Army drew its regiments from countless inhabited worlds and systems. Some came from generations of fine military tradition, while some were little more than barbarian mobs herded into and out of landercraft, or worth yet enslaved non-compliant prisoners or penal battalions formed of the worst criminals from across the galaxy. These, understandably, could not be readily counted upon to comport themselves with the professionalism that circumstances sometimes demanded. Yes, a penal battalion could be loosed on an enemy population where collateral damage was no issue, but they would be worse than useless if sent into, say, the toxic atmosphere of a Xenos Hive settlement, or the narrow confines of a Void Archaeology that needed recapture. What should happen, should the great crusade encounter such a task, but the Astartes were unable to provide their unique brand of war-making? No, then, but this is a record of those for whom the Imperium would assign such operations, the most professional unaugmented soldiery flying the Imperial Aquila, the Solar Auxilia. As detailed in a previous record upon the subject, the Solar Auxilia saw their origins in the Saturnine moons of the Sol system, derived from the Void Hoplites formations of the Saturnine Ordo, the military body that was formed from the various polities of Saturn's planetary nearspace. Over the course of the great crusade, that the Auxilia had been involved in since the first extra-Solar expeditions left the light of Terra's sun, they became known to the officiomilitaris as the singular heavy Void infantry formation of the crusade. From the outset, the Void warfare talents of the initial ten regiments, structurally unchanged from that of the Saturnine Void Hoplites, were immediately noticed and employed to great effect, leading the officiomilitaris to assign to the Auxilia Void structure clearance operations hazardous environment combat and boarding action engagements. This was, conditionally, extended when called for, forming what the Exertus Imperialis would dub interface operations, where regiments would be expected to, for example, clear void structures in the planet's orbit before transitioning to ground combat operations due to strategic exigencies. The tactical doctrine that evolved around this was primarily due to the technology that the regiments were so adept with, and, importantly, had ready access to. With Saturn's nearspace being, at the time of their founding, a loose collection of lunar colonies, space stations, and artificial environs of every form, the original Void Hoplites were forced to constantly fight in naval boarding actions and pressurized environments that, by sheer nature of combat, could not be counted upon to remain so. To this end, the Ordo developed its signature Void armor. The suit is fully sealed, allowing four operations in a vacuum, but additionally resistant to small arms fire, shock trauma, and possessing a self-healing skine to prevent minor lacerations or punctures from becoming an issue during combat. It is also especially resilient to radiological, toxicological, and thermal hazards, making it perfect for all kinds of Void operations. It should be noted that while formidably advanced compared to the flak armor of the Imperial Army, Auxilia Void armor is by no means a match for Legion as a starty's power armor, which surpasses solar patterned plate in every single capacity by many orders of magnitude. The fundamental structure of the solar Auxilia is something of a hybrid. Early regiments were arranged on the patterns of the Principia Bellicosa, comprising nominally of 5,000 soldiers under a legate colonel and his staff of logisticians, specialists, and political officers. This overall pattern did not last long, as with the demands for the regiments of the Auxilia grew more and more frequent across the expanding Crusade frontlines, the official militarists took steps to expand their most effective baseline human formation, restructuring the solar regiments into cohort formations intended to maximize autonomy and efficacy. Based on the fact that the cohort structure employed by the Pan-Pacific Empire of the Tyrant North and Doom during Terra's Unification Wars, the solar cohort could count around 120,000 soldiers under the banner of its Marshal Solar, but these could easily and effectively be subdivided into formations of 1200, with these sub-cohorts reporting to a more junior officer, be they a legate commander, commander, or sub-commander depending on both unit operational level and status. The formation around which these cohorts revolved was a hold-over from the days of the Ordo, the Tercio, comprised of three sections of Auxilia, all of which could be formed around whatever troops the cohort would require. The standard line formation was the Infantry Tercio, made up of three sections of twenty Laz rifle-armed Auxilia. These could be supplemented by the elite Velotaris Tercio, three units of ten veteran soldiers with an array of specialized weaponry, or supported by the Fire Support Tercio, three batteries of support and heavy weapons platforms, of which the Auxilia showed a notable preference for the tracked Rapier pattern. Command was rigid and expansive. A cohort, or collection of cohorts, were under the purview of the Expeditionary Commander, a Lord Militant or Lord Solar depending on whether their origin lay in the Imperial Army Regular or a Solar Auxilia Regiment. But the Auxilia, nominally under the umbrella of the Imperial Army, had a title on standing with the highest rank a baseline human could attain within the Imperial Military, speaks to their elite status within the Imperium. A Lord Solar possessed equal authority to that of any within the hierarchy of humanity, the only beings above them being the Emperor and those in possession of his own writ, namely the Primarchs, the Sigillite, and the Ligio Custodis. Their own personal assets were many and varied, depending on both career and personal preference. Generally speaking, each would possess a personal flagship, usually capital class, staffed with the entirety of their staff and household, including everything from elite lifeguards, indentured servants, intelligence officers, retainers, bursars, and emissaries and agents from all across the Imperium, the latter drawn to or requested by one of the highest military authorities in the galaxy. The flagship would also serve as a headquarters for the Strategic Operational Command, comprised of many varied officers of the Tribune's General, a Physio Locum Stratigus, and representatives of the Armorium, Munitoria, a Physio's Medicaid and Lectatio, and the Discipline Corps. While the naval officers of the cohort were also present, the leading admiral was ultimately subservient to the Lord Solar, with the latter often exercising more control and say in naval matters than Imperial Army Lord Militants on account of the Lord Solar's exclusively void-based nature. Attached Mechanicum elements were nominally under the Lord Solar's command, although in practical terms the forces of Red Mars could operate with a much higher degree of independence, owing to the revisions of the Treaty of Olympus. The command staff within the Auxilia, from the non-commissioned officers all the way to the Lord Solar, adhered to the chain of command with the Discipline rarely thought capable of baseline humans, as since the days of the Ordo, Discipline and Cohesion were given paramount importance within the doctrine of the Regiments. In the close confines of a boarding action, a minor infraction could result in the loss of an entire tertio of Auxiliaries. Soldiers who were found lacking during training would be immediately dismissed and reassigned, either to a less demanding Imperial Army Regiment, or to simply serve as a naval rating on one of the Auxilia's ships. Soldiers who broke rule during their service would face the harshest punishments meted out outside of a penal battalion, but those who shirked from duty, or infringed upon the Auxilia's standards during active battle, would simply be summarily executed by their superior officer. It has been noted that, while other Exertus Imperialis Regiments would possess dedicated disciplinary or political officers to carry out such swift and terrible disciplinary actions, the Auxilia did not, leaving this duty too, as noted, line officers. Certain there were none better suited to the role. It was the belief of many within the Exertus that the political officer's detachment from interpersonal relationships would be needed to carry out battlefield executions. But it was apparently no such concern for the officers of the Solar Auxilia, and must stand as a testament to their utter dedication, to the comportment of their duty in battle, and the primacy the Auxilia as a whole placed upon such military obligations. This level of near-superhuman discipline allowed the cohorts of the Auxilia to operate at a level of professionalism far exceeding that of the Imperial Army, and in doing so heavily influenced their tactical preferences on the battlefield, while primarily deployed for void-based operations. Necessity and situational demands often required them to make planetfall, which the Auxilia was well prepared for. Ground operations would often be conducted in the spirit of aggressive defence, involving the cohorts seizing the most defensible land possible, and luring the enemy into attacking them on the most favourable terms possible, up to and including the construction and deployment of prefabricated fortifications. When offensive manoeuvres were called for, they would either come in the form of a slow rolling advance, utilising as much armour and air support as was available, or selectively targeted lightning assaults upon critical portions of the enemy line, intended to minimise Auxilia losses. That the Auxilia was able to conduct these operations with its customary discipline is a testament to both their professionalism, and also the simple nature of their combat theatres. On a hostile alien world with an unbreathable atmosphere, or within the metal shell of a void-archology, fleeing was simply pointless, as there was just no line of retreat. Breaking the line dooms oneself and one's comrades, better to fight for them, for yourself, and for the Emperor, than simply die. Despite their fleet-based nature and primary role, the Solar Auxilia did not lack for an armour pool. Each cohort was expected to maintain an armoured reserve capable of transporting every auxiliary under its command purview, as well as field the requisite battle tank support in case Imperial Army armoured support was not available. The DracoSan Armoured Transport was preferential, possessing inherently better radiological, chemical, and toxicological protection than the nearly universally ubiquitous Rhino APC, as well as having the capacity to transport an entire las-rifle section. This environment-proofing demands extended to the Solar Auxilia's combat armour, while a cohort would possess ostensibly the same tank pool as an army regiment, all were constructed to be void and environment proof, with internal life support systems for the crews. Such was the Auxilia standing within the Imperium, that these designs were custom-built first upon Mars, and then on selected Forge Worlds deemed worthy to produce the now iconic Mars Solar patterned Lehman-Rus, Basilisk, and Medusa tanks. At least one super-heavy demi-cohort would also be included, generally featuring Malkador or Baneblade battle tanks, and occasionally more specified variants of the latter, such as a Shadow Sword or Storm Hammer. Noticeably absent from any Auxilia armoured company were static artillery batteries or specialized siege weaponry, as participation in siege or attritional warfare was considered by both Auxilia and higher Imperial command to be a criminal waste of their talents. By the outbreak of the Horus Heresy, it was determined, based on available records, that the Solar Auxilia comprised of 25% of all unaugmented human soldierly within the balance of the Exortus Imperialis. They were to serve with distinction, alongside the ranks of the loyalist legionnaires and starties throughout the years of that most heinous of conflicts. The Manichaean conquest, a campaign of the Coronet Deeps, the Solar War itself. Alas, these records must wait for another day. Until such a time, Ave Imperator, Gloria in Excelsis Terra.