This is the history of the Iron Warriors, one of the Chapters of Space Marine in the Warhammer 40,000 Universe.

'Iron Within, Iron Without' Iron Legion battle cry

The Primarch. Like the other twenty Primarchs, Perturabo was spirited away by the forces of Chaos when still an infant. The forces of Chaos wished to stop these children growing into the leaders of men which they would be. Perturabo was carried to the distant land of Olympia. He was discovered climbing through sheer cliffs below the city state of Lochos. The guards who found him took him before the Tyrant Dammekos. The Tyrant welcomed the boy into his household and raised him as a son, although Perturabo never trusted him and always responded coldly to affection. Dark and moody with a mind like a razor, he quickly rose through the ranks of the army of the Tyrant of Lochos. When he was found by the Emperor he was Warlord and it was clear to the Emperor that he was a master of siege craft. Perhaps it was a twist of fate that the world on which he had landed could teach him nothing except his own superiority over men.

The Legion The Emperor gave him command of the Iron Warriors Legion who had been created during the Primarchs absence. The Legion shared common characteristics with their Primarch, despite having never met him. They enjoyed an affinity with technology and displayed a cold, efficient logic when tackling a problem. This tragically resulted in the turning of the Warriors, as they found themselves facing a threat where the only defence was total, unshakeable faith.

As the Iron Warriors advanced with the Great Crusade re-conquering worlds, they established citadels which guaranteed a safe line of communication. Tiny numbers of Warriors were left to garrison these fortifications. Unlike some of the other Primarchs who refused to split their forces, Perturabo obeyed his orders with increasing bitterness. The Legion was becoming a garrison Legion with small deployments all through the Imperium. Within the infamous Iron Keep on Delgas II was only one squad of ten Iron Warriors, despite the world having a population of over 130 million. Resentment began to build in the Legion and with the Primarch in particular.

The Iron Warriors were devastating siege troops. Cross trained by the Tech Priests of Mars, the quickly built on their already impressive reputation. However the nature of siege warfare is for long periods of dull and back breaking work only broken by short bursts of the most brutal, merciless combat imaginable. Combat fatigue began to affect the marines, who were not immune to the toll that this sort of combat had on their minds. The custom was that once the siege lines were complete the opposing side must either surrender or expect no mercy. As time went on the Iron Warriors came to prefer the later as it was a release from their life in the trenches.

It was well known that Perturabo was envious of Rogal Dorn, Primarch of the Imperial Fists. After Dorn's comments about the Imperial Palace being safe against even the Iron Warriors attacks his jealousy and anger grew.

The other Primarchs tended to keep Perturabo at a distance, although this may be because they feared his technical genius that was far in advance of any other Primarch. In the recordings of the routing of the Orks of Overdog Mashogg, Perturabo only features as the 'comrade' who calculated the optimum way to bypass the low orbit defences.

The Horus Heresy It fell to Horus to tell Perturabo that his home world was in rebellion. Dammekos had died and the people had taken to arms. By this time the Primarch was tired of having to prove his worth and the thought of his Legion being unable to hold its own home world appalled him. Horus capitalised on this opportunity. Before his departure, Horus presented Perturabo with the hammer Forgebreaker. It is possible that the weapon acted as a conduit through which the forces of Chaos could manipulate the Iron Warrior Primarch. Alternatively, a mark of respect from such a leader as Horus could have signalled the sealing of a pact between the two.

Perturabo and the Iron Warriors suppressed the rebellion on the streets of one city-state after another. No one was spared. It was the principle of surrender or no quarter, and the Iron Warriors had grown accustomed to granting no quarter. Perturabo watched on unmoved and cold as the fortifications in which he taken such pride were overcome. By the time the massacre was over, Olympia had been culled into slavery with almost 5 million civilians dead.

As the pyres burned through the long Olympian night, the Iron Warriors slowly realised the extent of what they had done. One moment they were humanity's heroes assaulting the Hrud and the next they were committing genocide. Perturabo was like a man emerging from a drunken stupor who finds blood on his hands, only dimly aware of how it got there, but is aware of an oppressive reeling of shame nonetheless. He knew that the Emperor could never forgive him his crime.

It was now that they received the worst news possible. The Space Wolves had attacked the Thousand Sons on Prospero. Horus had turned against the Imperium along with the Sons of Horus, Angron's World Eaters and Mortarion's Death Guard. The Emperors Children had tried to reason with Horus but had joined him instead. The Iron Warriors realised that what they had done was nothing compared to what was going on in the Imperium.

The events that followed have become legend. The Iron Warriors were ordered, along with six other Legions to face Horus on Istvaan V. The Iron Warriors joined the Night Lords, Word Bearers and the Alpha Legion and destroyed the three remaining loyal Legions. The Warriors were now let loose and on a dozen worlds an Iron Warrior Warsmith replaced the governor and tithes were paid to the Legion.

A large section of the Legion followed their Primarch to Earth, where they supervised they siege of the Emperor's Palace. They found a sublime pleasure in cutting through the defences of the Palace which had been declared impervious to all comers. However, with the fall of Horus, the Legion retreated to the Eye of Terror, seizing a new world where they could plan and brood on the events that had occurred.

The remaining troops defended their fortress on Olympia. The Imperial Fists, led by Rogal Dorn laid siege to the fortress and with the aid of the Ultramarines crushed the Warriors. The garrison held out for two years and in the end they triggered their missile stockpiles, leaving only a blasted wasteland that was declared Perdita.

Eye of Terror Like the other Traitor Legions, the Iron Warriors have control of a planet within the Eye of Terror. Knowledge about these worlds is scant at best, although what is known is Medrengard is a world transformed into one giant fortress, towers plunging toward the sky. How accurate this is no-one can say, since the Iron Warriors always designed with defence and strategy in mind.

Inquisitor Maul performed an extended reconnaissance of the Eye of Terror in M.38. Although he was not cogent upon his return, his ship's interior bulkheads were covered by script in the Inquisitor's own blood describing what he had seen. Medrengard was described as a bleak gaol world where slaves toiled and died while great Chaos warships were tethered to its tallest towers wherein resided the Warriors themselves.

In battle the Iron Warriors are devastating. They concentrate all their fire on one point of weakness and maintain this barrage until the breach has been opened. Once this is done they will probe it with veterans until the gap is prised open enough for a storming force which can push the attack through. Once they have the enemy at their mercy they prefer to destroy them at their leisure, happy to let bombardment do the work for them. They have amassed a massive arsenal of siege weaponry over the years as well as artillery and planetary landing craft.

They, like all Chaos Legions have little organisation, tending to be led by Warsmiths and fighting against loyal Marines and civilians alike. They experience less mutation than other Legions, although there is a marked paranoid streak through them. The Iron Warriors believe that the Emperor used them to fight the bloodiest battles of his Crusade and then let the other, more favoured Primarchs take all the glory. They also believe that Rogal Dorn turned Olympia against them so that they would be disgraced and discarded after they had served their purpose. They will have vengeance on both.