Iron Warriors - Bitter Resentments: The wedge that had been hammered between the Iron Warriors and the other Space Marine Legions, however, was only driven home further as time passed, and resentment, pride and paranoia gathered in the hearts of many within the IVth Legion. By his grim methods and savage example, Perturabo had awoken in his warriors a reflection of his own dark soul, and within them his own suspicions, malevolent distrust and callous indifference to life grew alongside the ruthless determination, cold intellect and strength he wished to unlock there.It is then perhaps not unsurprising, given the IVth Legion's predilection for open battle, its employment in siege assault -- the most dangerous and unpredictable of all forms of line warfare -- and its willingness at every level from its Primarch downwards to accept attrition as the price of victory, that the Iron Warriors are estimated in many sources to have suffered the highest overall number of casualties over time of any of the Legions in the Great Crusade.It is also similarly a testament to them and the cold and cruel genius of their Primarch, that such losses were routinely absorbed by the Legion without serous lasting depreciation of the Iron Warriors' strategic fighting power and that high casualties rarely resulted in defeat for the IVth Legion. However, despite their genetically enhanced resilience to mental trauma and psycho-indoctrination, it is believed that such a continuous exposure to loss and destruction worked a slow and bitter corrosion on the Legion's psyche.Perturabo and his Legion sought no friends or allies amongst those they served with, save perhaps the agents of the Mechanicum who aided them in the pursuit of ever more powerful and efficient means of waging war. In their fellow Legions they saw weaknesses bred by self-deceit, lack of discipline, false mysticism and vanity, and they also saw insults and slights by them, both real and imagined.Even many factions of the Mechanicum, to whom Perturabo's technological intellect was a wonder, did not trust him or his Legion fully, dangerously self-sufficient and adept as they were, and ignorant of the doctrines of the Omnissiah's faith.To the forces of the Excertus Imperialis -- the hosts of the Imperial Army and its auxiliaries -- the Iron Warriors' repute was a dark one indeed. More than any other Legion, the Iron Warriors were seen as not only willing to use the lives of merely human auxiliaries as a strategic resource, but as deliberate expenditure, as cannon fodder to deplete an enemy's firepower, in sacrificial waves by the thousand to bring out a foe from their defences, or simply to gauge an enemy's strengths by observing how fast they could annihilate them.Such repeated incidents only served to further taint the hated epithet the "Corpse Grinders" among the common soldiers of the Great Crusade. Open mutiny, put down with predictably thorough slaughter, grew increasingly frequent in war zones where Excertus Auxillia were under the Iron Warriors' command until, by the Warmaster Horus' edict, a standing order was effected to ensure that the bulk of such troops given to the Iron Warriors' command were to be either indentured criminals or enslaved non-Compliants to ameliorate the corrosive effect on wider morale.By the last solar decades of the Great Crusade, rivalries as well as often mutual simmering disdain, such as the antipathy between the Iron Warriors and Raven Guard Legion brought on by friction during the Icessunder War, and an increasingly bitter rivalry between the Iron Warriors and the Imperial Fists, characterised the Iron Warriors' relationship with its fellow Legions.Indeed, even where the Iron Warriors and their Primarch fought successfully alongside their fellow Legions, such as in the critical war against WAAAGH! Mashogg, their part was often treated with indifference or guarded disdain by the IVth Legion's contemporaries.In this latter incident for example, although before Perturabo and the Iron Warriors' arrival in the war zone, Overdog Mashogg's vast orbital fortifications had previously repulsed attack after attack from both the Space Wolves and the White Scars Legions.Perturabo, whose plan succeeded at last in breaking the line and allowing for the Orks' slaughter, is recorded in the contemporary chronicles of his brother-Legions only as a nameless "comrade-in-arms." This growing schism, perhaps more obvious in hindsight than it would have appeared at the time, was further exacerbated after the appointment of Horus as the Imperial Warmaster.This major re-alignment in the deployment of the Great Crusade saw the renewal and issuing of a string of directives and disposition orders, some from Terra and others from the Warmaster. These orders continued to bleed the Iron Warriors Legion and scatter a good part of its strength across a myriad of splinter Expeditionary Fleets, thankless sieges and garrison postings in the most dangerous, forlorn and isolated corners of the ever-widening Imperium.Meanwhile, Perturabo's own 125th Expeditionary Fleet was driven into the teeth of deadly foe after deadly foe, neither asking for, nor being sent reinforcements or additional resources, save for those it could itself generate and acquire. Perturabo, bitter but iron in his word, complied.Such events in retrospect only served to foment and amplify the resentment and discord within the IVth Legion and split it from the Imperium it served, and increasingly to derange its warriors in the face of some of the worst horrors the Great Crusade would ever face. Indeed, such may have very well been Horus' plan.As the Great Crusade moved forward, many Iron Warrior citadels were established on liberated worlds, guaranteeing a safe line of communications and an Imperial occupational force for the planet. Small units of Iron Warriors were garrisoned in these new fortifications, sometimes in ridiculously small numbers. One often-cited example was the Iron Keep on Delgas II, where a single Tactical Squad of ten Iron Warriors was stationed, despite the world having a disgruntled population of almost 130 million people.Where other Primarchs like Leman Russ, Vulkan and Magnus the Red refused to split their forces, Perturabo obeyed his orders with increasing bitterness. The Iron Warriors were being turned into a garrison Legion, with tiny deployments all over the Imperium. The Iron Warriors' indisputable success in siege warfare led to them being "typecast" so that they became the automatic choice for any siege or garrison mission, ignoring the basic needs of all the Legion's Astartes for rest and reorganisation. Resentment against the Emperor's relentless demands began to build up throughout the IVth Legion, and particularly within Perturabo himself.