Iron Hands - War Disposition: At the outset of the Horus Heresy, the Iron Hands Legion is commonly estimated to have had an operational strength just in excess of 113,000 Astartes, with a huge operating reserve of wargear and supplies, alongside a diverse fleet of around a hundred capital vessels of various classes.This placed the Iron Hands within the mid-tier of Space Marine Legion strengths recorded at this date by their sheer numbers alone, but in general terms, their resources in wargear, war materiel and supply made them a considerably greater military power in practice than their sheer number would suggest.At the time the events of the Isstvan III Atrocity were taking place, the major constituent of the Legion (believed to be around two-thirds its full strength both in terms of manpower and ships, comprising the majority of its most powerful Clans), were under the direct command of their Primarch, forming the 52nd Expeditionary Fleet. Owing to the perfidious treachery of Fulgrim, and the uncontrollable wrath of Ferrus Manus in response, the Iron Hands Primarch broke ranks from this force and reached Isstvan V with only an elite cadre chosen from his then-favoured Avernii Clan alongside him, almost all of whom were annihilated with their slain Primarch during the Drop Site Massacre.A great many more vessels of the 52nd Expeditionary Fleet following on behind their Primarch were also destroyed, along with tens of thousands of Iron Hands on board as they later transited into the Istvaan System, rushing unknowingly into a death trap from which only a few of the Xth Legion's warships were to escape.Taken together, these losses were great, although this left more survivors from the Iron Hands Legion in number than could be ascribed to the Drop Site Massacre's other victim Legions overall. This was largely the case as larger groups of Iron Hands were presently engaged elsewhere and unable to heed, or ignorant of, their Primarch's rushed call to assault the Traitors at the Istvaan System. The Legion was nevertheless savagely reduced; the survivors scattered physically and shattered spiritually by its losses.Initially sent reeling and psychologically devastated, the Iron Hands Legion's survivors fractured, and the full story of what happened to its scions remains clouded to this day. It is known, however, that some Clans re-organised a council of Iron Fathers on Medusa to take charge of the ravaged Legion, and sped the recruitment and creation of new Space Marines from the extensive stores of gene-seed kept there with the goal of rebuilding the Legion.Alongside this, it is widely believed that in the aftermath some Iron Hands units and, in some cases, entire Clans shunned the Medusan Iron Council's assumed authority and went their own way, consumed by their own hatred and need for revenge. These fractured forces fought their own war and it is widely believed some delved into the use of dark and forbidden forces from Humanity's ancient past to do so, although this has been strenuously denied since by the Iron Hands Clan Council.What cannot be contested, however, is that other lone Iron Hands and small scattered groups cast off their Legion's livery entirely and either fought on alone or went Renegade -- Iron Hands no more. Regardless of the hidden truths of these terrible times, the Iron Hands Legion in the years that followed the Drop Site Massacre, and largely under the auspices of the Medusan faction, managed to re-enter the fight against the Traitors during the Horus Heresy and Great Scouring with devastating results on several outer worlds. But it was as a shadow of its former strength; no longer a Space Marine Legion whole, united or even entirely sane.