Iron Warriors - Brethren of the Iron Warriors: There existed in the ranks of the Iron Warriors a series of long-standing warrior societies that existed outside of the Legion's military order and command structure, and which seldom became known to outsiders. By some accounts these were so firmly entrenched that they resisted the outside and corrosive influence of Horus' Warrior Lodges, and by other accounts became the vector of the IVth Legion's corruption. These warrior societies included the following:Dodekatheon - The Dodekatheon, also known as the "Brethren of Stone," was the oldest, most numerous and influential of the warrior societies of the IVth Legion. The Brethren of Stone was an order of masons and strategists whose origins predated the Legion's connection to Perturabo and Olympia. Originating first as a tactical symposium in the style of the Warcaste Metistraad culture of Terra, it focused on siege craft as well as the field of military architecture. Upon Perturabo's re-joining with the IVth Legion, the primarch massively expanded the organisation, renaming it the Dodekatheon after the cultural and political traditions of Olympia. The Olympian Dodekatheon was a cyclical gathering of the twelve greatest Tyrant households of Olympia for the purposes of resolving disputes and forging allegiances. It also featured extensive wargames and tournaments between the households present, and the matter of artisans and warriors, who would show off their skills either to the glory of their patrons or in the hopes of employment. The IVth Legion's Dodekatheon took on these trappings, becoming over time a venue of contest and exchange for its foremost warriors, officers, builders and strategists -- met without rank and on equal footing -- to test their mettle and further their learning. It was where its members fought and re-fought bloodless wars in simulation, unveiled new designs, poured over battle reports and military intelligence, and vied for position and the respect of their peers and their primarch. Although Perturabo enforced rigid discipline in his Legion and would countenance no disruption due to vendetta, the Dodekatheon served as a well-spring for the Legion's internal rivalries as much as an academy of war. In theory the Dodekatheon was open to all Iron Warriors, but in practice only those who had distinguished themselves in war attended, others did not, rather than risk offending their primarch.Apolakron - The Apolakron, known as the "Brethren of Steel," was a smaller shadow organisation in the Iron Warriors Legion which operated in many ways as a division of the larger Dodekatheon; the Apolakron's particular focus was on machine-craft; Battle-Automata, both in their construction and maintenance, and their employment in war. It existed in an uneasy alliance with the Mechanicum, save those Tech-priests who had long-served the Iron Warriors directly and was viewed with particular suspicion by elements of the Legio Cybernetica, who saw it not as a kindred group, but rather a rival to their monopoly on the arcane knowledge of robots they held.Kheledakos - The Kheledakos, known as the "Brethren of Cold," owed its origins to the aftermath of the IVth Legion's early campaigns under Perturabo. The Kheledakos, although led and commanded by Astartes, also encompassed the mortal senior officers and Mechanicum magi, engineers and shipwrights who maintained and crewed the Legion's warships. Its base of operations was the Black Citadel, Olympia's principal and most heavily fortified orbital shipyard, and void warfare and the construction and design of warships and assault craft were its obsession.Lyssatra - The Lyssatra, known as the "Brethren of Thunder," were the most obscure and cult-like of the Legion's warrior societies, and were disparagingly known within the IVth Legion as the "burned men." It was something of a pariah group whose members contained some of the Legion's more unhinged and war-brutalised gun-crafters, weaponsmiths and ordnancers. Their obsession was creating destruction and devastation, far beyond what even the rest of the Legion generally considered sane or practical, and were darkly rumoured to have had truck with strange occult ideology and xeno-technology in secret long before the outbreak of the Horus Heresy.Tyranthikos - The Tyranthikos or "Dominators" were an elite formation of Terminators exclusively utilised by the Iron Warriors. Once they had been the honour guard of Primarch Perturabo himself, and high in the esteem of their primarch and Legion, but their failure at the Battle of Phall in 007.M31 would see them reduced to the miserable state in which they existed during the Horus Heresy. The Dominator cohorts existed in purgatory, stripped of the honours once bestowed upon them by their primarch and forced to serve in the forefront of the most gruelling assaults. The Iron Circle Battle-Automata that had replaced them as Perturabo's honour guard were an ever-present reminder of their failures during the opening salvos of the Horus Heresy and became the focus of their malignant disdain.