Horus Heresy - The Sundered and the Black: Almost from the outset, the war of the Horus Heresy was a vast cataclysm and one whose events moved with such quicksilver pace that mystery, supposition, lies and simple ignorance cloaked much of the bloodshed even as it occurred, casting a veil over much that would never be lifted. Though the roll call of Space Marine Legions, Titan Legio, Auxilia regiments and Mechanicum Taghmata that sided with the Arch-Traitor and those who remained loyal is largely known and accepted, the full truth is far more complex and far more mysterious than commonly believed.Of those who fell at Isstvan, there were survivors, remnants and fleeing fragments shorn of command and driven half mad by treachery; from that point onwards they were isolated, alone. These were the shattered Legions and, while some swiftly returned to the Imperial fold, some did not or would not. Some would go on to wage a bitter war of vengeance alone, some would simply disappear, their fates unknown, their stories untold. But there were others of a darker hue. It has long been refuted since, but is indelibly the case, that in the Legions that remained loyal to the Emperor there were elements, sometimes whole companies and commands, that did not. In some cases the infection of the Warmaster's "Warrior Lodges" has been blamed, while in others perhaps grievances long-smouldering were the cause, just as infiltration by outside forces, or simply a darker truth applies that, given the option, some Astartes believed Horus had the superior cause and the superior right to command their allegiance, not the Emperor, while some retained a loyalty to their Emperor and the Great Crusade over that of their own Primarch's will. It is true that particularly in the early years of the war, detachments of Legiones Astartes and sometimes entire squadrons of warships simply vanished without apparent trace, and while many may have fallen foul of Warp Storms and enemy action, it is likely just as true that some quietly slipped anchor and turned their coats to serve another master, and that this happened on both sides of the divide.Thus can perhaps be explained, at least in part, persistent stories and evidence long since suppressed of midnight clad warriors in defaced Night Lords heraldry savagely attacking Traitor forces at the liberation of Estaban III, or of recurring reports of multiple Space Marine strike forces seemingly in the resurrected livery of the Dusk Raiders thwarting the Iron Warriors at Kibron and Malinche's Fall. Likewise also should be considered the long-denied evidence of a Great Company of the Space Wolves Legion bearing the symbol of the Serpent's Eye slaughtering millions at Neo Cadiz in 008.M31, or of a company of Legiones Astartes present at the Siege of Mezoa bearing the hybrid arms and panoply of the Iron Hands and Sons of Horus Legions both. These were merely a handful of still infamous cases, but there are many more unsubstantiated or simply now forgotten which paint a more complex and uncertain picture of this great civil war than is normally accounted. Further to this, and perhaps an even more sinister enigma, are the persistent reports of Space Marine forces appearing bearing no sign or seal of heraldry or origin at all, or stranger yet, heraldry which bears no mark known during the Great Crusade, although whether the "black" Legionaries were merely turncoats or, as some have whispered, perhaps raised by the Traitors from the chimeric gene-seed of the Isstvan dead for their own terrible purposes, none can now say for certain.The term "Blackshield" came to be used during the period of the Horus Heresy known as the Age of Darkness in the early 31st Millennium to cover a wide range of Space Marine outcasts, marauders and those Legiones Astartes of uncertain allegiances or origin. Mystery and suspicion attached themselves to such warriors regardless of their true loyalties or intentions, and while some did deliberately scour their old heraldry from their armour or replace it with some false device or heraldry of their own, their name of Blackshield was often a literal description for armour over-masked or simply scorched black.Though never existing in numbers so great as the Legions from which they had no doubt sprang -- far from it -- each faction and band, from the dozen survivors of a deadly betrayal by their own kind who cast aside the past, to the cohort of rapidly indoctrinated initiates thrust into battle for a cause they barely understood in Power Armour empty of livery, had their own place in the tapestry of galaxy-wide destruction that was the Horus Heresy.The motivations and goals of those forces dubbed Blackshields by the warlords of the era and the historians of later times were as individual as their bands. Many ultimately can be categorised as believing (rightly or wrongly) that their Legion or Primarch was no more, or on the opposite side of the coin renounced their Legion and their sire, refusing to follow his example in siding with one faction or the other in Mankind's galactic civil war. In such ways did so-called "traitors" draw Traitor blood and -- albeit more rarely -- did scions of Legions that remained steadfastly loyal turn upon their Emperor and their brothers. The more shadowy and less understood of the Blackshield factions remained cloaked under a shroud of misdirection and secrecy. These were Legionaries created using dangerously accelerated or forbidden chimeric gene-seed implantation and brutally expedited psycho-indoctrination protocols to quickly replace catastrophic losses as the certainties of the early years of the war gave way to the grim realisation that neither side might have enough Space Marines and materiél to overwhelm the other, and while many programs were put into place for the Legions to accelerate recruitment by the Legions themselves, other, darker and more hidden endeavours were undertaken by the powers of both sides outside the "legitimate" framework of the Legions that had gone before, uncaring of established practice or traditions, or indeed risk, needing only results.Of those Blackshields who were truly rogue, many still fought their war with a bitter fervour that matched any zealot in either the Warmaster's or the Emperor's cause. While others, perhaps starting on their path through a simple drive to survive, became reavers and renegades intent upon forging their own destinies among the stars. Of these some began to corrode in mind and spirit as time and the tide of war ground on, degenerating into little more than madmen and wanton killers, while others eventually regained a place, although often a distrusted one, in the order of battle of one great faction or the other before the end. Of those who did not, most would find the Great Scouring that was to follow their bloody ending, or be driven into the darkness beyond known space.