Iron Warriors - Pre-Heresy: Within the Iron Warriors Legion Perturabo's word was law. To him there was never any differences between Terran and Olympian Astartes; all were his Iron Warriors, grist for the bloody mill of war. Although for many solar decades the IVth Legion had been rigidly dogmatic in its adherence to the patterns set out for the nascent Legion at the start of the Great Crusade, Perturabo's intervention was to write significant and far-ranging changes upon his Legion, but not one that by any means changed it beyond all recognition from what had gone before.This was a process that was swift and thorough as well as entirely done to the primarch's exacting planning. While informed by the sophisticated martial culture of Olympia of which Perturabo had been a part, it also had its origins in Perturabo's rapacious learning in the time he spent at the Emperor's side and on Terra itself. Here he is known to have devoured much of Humanity's known martial traditions and histories, transforming that learning with his own inherent genius and predilections into what would become the template for the Iron Warriors.The resulting principal strategic building block of the Iron Warriors Legion was the "Grand Battalion." This formation, although roughly analogous in organisation role to the units known as "chapters" in the other Space Marine Legions as envisioned in the Principia Belicosa, with 1,000 Space Marine Legionaries as its notional strength, also incorporated a very substantial portion of standing armour, artillery and logistical support elements, far beyond that found in other Legions at the same organisational level.Furthermore, allowing for the higher than standard state of attrition in the Iron Warriors Legion, particularly among initiates in the first standard years of their service, recruitment and reinforcement into a Grand Battalion in a war zone was continuous, which caused the strength of any given Grand Battalion to fluctuate widely. This was particularly the case in more extreme circumstances where severely depleted Grand Battalions were simply folded into other active units. Documentary evidence exists of particular Grand Battalions operating with as little as 500 Legionaries and as many as 5,000 in extreme cases.Organisation below the strategic level was highly stratified, but just as equally and pragmatically varied by the demands of the particular operations and deployments, with common divisions rated as "Cohorts" or "Grand Companies", which were heavily mechanised and reinforced units comprising three to five line companies of Legionaries and their attendant Human auxiliary troops, Mechanicum detachments and integrated support structures.Below this were the "Line Companies" and "Armour Centuries," comprising roughly 100 Legionaries or 20-50 armoured units, down through sections and individual squads. Whilst across the Legion's Grand Battalions were seeded elements of the Tyranthikos -- the "Dominators" -- a Veteran core of line breakers and assaulters who had each survived a score of desperate and bloody sieges to receive the name, and were the foremost proponents of the use of Terminator Armour within the Legion.At every level the Iron Warriors Legion was formidably provisioned in arms and wargear, from several thousand operational suits of Tactical Dreadnought Armour of every pattern to munitions reserves estimated to exceed that of several other Legions combined. The technical aptitude of each Iron Warrior was also formidable, furthering the functionality and customisation of their personal panoply of war.In a customarily practical approach, the IVth Legion made extensive use of both specialised systems, such as dedicated sections of Astartes equipped with portable Lascannons for anti-armour warfare and Mark III Iron Power Armour for siege assault units, and patterns selected foremost for reliability and ease of repair for mass deployment and reserve supply on protracted campaigns. Merely aesthetic damage to wargear was deemed irrelevant, and while a Grand Battalion's muster might see rank upon rank of glittering steel presented for their commanding warsmith's inspection, a war zone's privations would see the Iron Warrior's armour increasingly bloodied, burned and battered over its duration, attended to only to restore basic functionality until victory was achieved.Of singular note within the IVth Legion was the range, number and diversity of the armoured vehicle and artillery support assets fielded by the Iron Warriors. These were known to include the full breadth of general patterns and designs operated across the Imperium by the Legiones Astartes, with tactical emphasis placed on heavy units such as the Land Raider and super-heavy war machines such as the Typhon, Stormblade and Mastodon. Additionally, the employment of very large numbers of "lesser" classes such as the Rhino, Basilisk and Predator was also common. These the IVth Legion largely considered disposable in practice, owing to their capacity to replace these patterns with ease thanks to the Mechanicum manufactoria permanently geared to their production in the Legion's service.In addition, the Iron Warriors were known to operate large numbers of more unusual variant main battle tanks and specialised war machines such as the Cerberus Heavy Tank Destroyer, Deimos Whirlwind Scorpius and Thunderstrike tanks. This bias and capacity of construction, alongside the integration of armoured and artillery formations at every level of the IVth Legion meant that the Iron Warriors had the largest armoured reserve and ordnance capacity of any of the Legions of the Great Crusade.A particular example of this was a specialised formation within the IVth Legion known as the Stor-Bezashk. In a Legion renowned for the power of its ordnance and its consummate skills in siege warfare, the Stor-Bezashk were the masters of destruction, tasked with the maintenance, construction and use of the deadly siege weapons and singular relics of destruction in the Legion's Armoury. The siegemasters of the Stor-Bezashk had command of weapons and war engines unseen outside of the ranks of the Mechanicum's Ordo Reductor and direct battlefield command of the Legion's extensive stockpiles of atomic shells, phosphex reserves and core gravitic munitions, and power of life and death over those Legionaries assigned (often as punishment) to the Destroyer cadre under the siegemasters' control. The Stor-Bezashk served both as a specialised siege breaking force in its own right and, broken into its component parts, as specialised reinforcements for the Legion's Grand Battalions in the field.Perturabo's ideal for the Iron Warriors can therefore be seen as that of an integrated, disciplined and unstoppable aggressive force. It was one that mastered warfare both in attack as well as defence, but if any single factor could be said to typify the Iron Warriors, it was their calculated savagery.Their bombardments were murderous works of art, precisely configured to overwhelm and to shatter. Their assaults were faultlessly choreographed exercises in armoured tactics and manoeuvre, supported by remorseless infantry advances that did not falter, regardless of the fire and fury with which they were met.When at last, after the storm of firepower and the crushing assault of the tanks, matters came to the bloody press of hand-to-hand were the darkest tempers of the Iron Warriors shown in a hateful ferocity the match of the burning rage of Angron's near-berserk World Eaters or the dolorous blade-work of Lion El'Jonson's Dark Angels. But even this last extreme of violence could be checked as abruptly as the throwing of a switch, such was the inhuman discipline that Perturabo both installed and enforced on pain of death from his Legion.It is clear that Perturabo saw his Legion not as a collective of individual members but as a cohesive and unified whole. An army whose task was to overwhelm their foes by the most efficient and direct methods of possible, destroy that enemy's ability to resist and, where needed, to exterminate them utterly.Glory and honour belonged to the IVth Legion as a whole, not to its rank and file or its individual warriors. More perhaps than any Primarch save Angron, it has been said that no Primarch saw his own Legionaries with so little regard as Perturabo, to him they were a resource to be spent to achieve victory, a resource which did have undeniable value, but a resource to be expended never-the-less.This thinking was reflected in the structure of the Iron Warriors Legion itself, which was stratified and operated in such a way as to absorb loss and create identity at a strategic, rather than tactical level. The IVth Legion itself was both a pioneer and proponent of the accelerated recruitment and creation of the Legiones Astartes, and an Iron Warriors Space Marine Legionary could expect to serve in a myriad of different units and roles, and under a number of differences to the more ritualised formation of many other Legions.Promotion and advancement in the Legion's ranks were a matter in the first part of survival, and in the second of specialisation should a Legionary display particular talents and aptitudes. Mere martial ability was not enough to measure a Legionary's fitness to serve, and each Iron Warrior was required to be an artisan of metal, machine and stone just as they were a line fighter, close-quarter killer and artillerist.In this their Primarch's gene-seed was evidenced and as well as technological aptitude, many Iron Warriors displayed extraordinary skill at rapid data-analysis, comprehension and abstract reasoning, and were likewise psychologically marked by a tendency towards suspicion, distrust and viciousness of temper, even among their own.While honourific and commendations in general meant little to the Iron Warriors at an individual level, technological skill and the ability to wage warfare in the manner which Perturabo favoured was recognised and rewarded. This was most evident in the rank of "Warsmith" within the Legion. In Perturabo's Legion, the title of Warsmith grew to largely replace that of Praetor and Lord Commander, and it carried with it much of the role of a traditional Olympian warlord as well as an embodiment of the Iron Warriors' strategic doctrines.A Warsmith was -- as perhaps the title implies -- required to fashion and mould a battlefield to their will, not simply to excel at fighting or indeed leading those who fought. They were expected to have a complete mastery of logistics, siegecraft, ordnance and the cerebral comprehension of war; from planning campaigns of planetary conquest to the rapid calculation of tactical fire zones in a shattered urban ruin.Unlike those of the lower ranks who fought at their command, a Warsmith was an individual in whose hands a battle rested, and the success or failure of the forces under their command was theirs to carry, to the good or ill of their own fate -- Perturabo being renowned as unforgiving of failure.This system made the Warsmiths a grim, self-possessed, often paranoid and highly independent class of savant-warlords within the IVth Legion. It winnowed the weak and the ill-fortuned from their number and left those who remained as the most adept, ruthless and intelligent the Iron Warriors Legion had to offer. The ranks of the Warsmiths, which fluctuated in number and seniority between them, was not clearly defined, leading to rivalries and feuds between them.The majority of Warsmiths commanded Grand Battalions of their own, making up the core of the Legion's strategic command structure, while others had command of specific strategic formations such as the Stor-Bezashk, important garrison posts and splinter Expeditionary Fleets, or held satrapies of Armoury Worlds and other detached commands.Three Warsmiths, granted particular favour by Perturabo, were exalted to a further rank, that of "Triarch." These three senior Warsmiths formed the Trident, who nominally served as their Primarch's council of advisors, but more commonly served to convey his will and direct orders to those below them. Such proximity to the IVth Legion's increasingly dark-hearted master, in particularly in later years, is reputed to have held dangers of its own.At the time of the outbreak of the Horus Heresy, the Iron Warriors Legion is estimated to have had an active strength of between 150,000 and 180,000 Astartes, along with a very substantial war fleet of over a hundred capital class vessels. More accurate assessment than this is, however, impossible given the considerable portion of sub-deployments and garrisons that were maintained by the IVth Legion scattered across the Imperium and its increasingly isolationist tendencies in the years before the civil war.It is believed that the Legion had further accelerated its indoctrination and recruiting program, as well as local shipbuilding at Olympia in the lead-up to the rebellion, and so the lower division of these estimates may indeed be erroneous.Further to this the Legion, according to evidence uncovered later, appears to have increased in ties to certain factions of the Mechanicum and the Legio Cybernetica in particular during this period, and is believed to have begun to shelter some Renegade or outcast elements of the Machine Cult under Perturabo's protection.It is also known to have raised up from the ashes of Olympia a fanatically loyal and highly-trained human auxiliary force, the Thorakara, as a tool of oppression and client army in its own right to serve the IVth Legion. These measures can now be seen as the beginning of the bloody "Empire of Iron," centred on damned Olympia, that was to take root in the years that followed of rebellion and civil war.So it was that rotting from within with loathing and bitter spite, the iron facade the IVth Legion presented to the Imperium and the extent of how rapidly and how deeply it had descended into homicidal madness was kept hidden. Only at last, when it was called on to help in the punishment of the rebellious Warmaster Horus at Istvaan V was the dark truth of its true allegiance revealed.