Blackshield - The Forms of Madness: Many individual Blackshields warbands would be identified over the course of the Horus Heresy, yet no two were exactly the same in constitution. Most would in fact bear almost no similarities to either standard Space Marine formations or other Blackshields bands, each a bewildering array of mismatched warriors and doctrines forced together by fate and dire circumstance.Observed strengths among these Blackshields warbands varied from as few as two dozen Astartes warriors to as many as 2,000, with a few hundred warriors being the most common force size. The strength of these warbands was almost always concentrated in its core infantry elements, for, divorced from conventional Legion logistical chains, stocks of heavy equipment very quickly dwindled in battle. It was rare indeed for such groups to utilise the heaviest vehicles and weapons once available to the Legions, and they relied upon the lighter, more commonplace combat assets. Indeed it is likely that many Blackshields raids were motivated more by the need to acquire arms and munitions than any interest in the wider war.The exact nature of their panoply varied, some equipped in the manner of a standard Legiones Astartes infantry company and others wielding weapons of alien provenance and dire power. Likewise, their methods of organisation were in some cases quite ordinary, with units forming ordered companies, while others defied all sane military logic.Given that some Blackshield warbands may have come into being as a result of accelerated gene-seed organ implantation regimes or unsanctioned gene-seed replication protocols, their unsanctioned and often dangerous orders of battle have their root in desperation and madness as much as any rejection of past traditions. However, despite these vast differences, scholars of the Horus Heresy would later separate these unconventional warriors into several loose categories, as explored below:Renegades - The most common warbands of Blackshields were those that chose to forsake their own primarch's choice of side in the civil war and fight against them on the battlefield. Some were the outcast sons of the Traitor Legions, true to their oaths to the Emperor but forever seen as tainted by those who ought to be their brothers, while others were those among the Loyalist Legions that were fool enough to declare for Horus and seek power among the damned. What separated these warriors from more common turncoats was their complete rejection of their old identity. They did not see themselves as Loyalist World Eaters or Traitor White Scars, but rather as something other, often viscerally removing the signs and symbols of their old selves. In battle they were single-minded in their pursuit of their former brothers and gene-father, often forsaking rational tactics in order to engage in suicidal assaults. In the eyes of such warriors even a single wound inflicted upon their old master was worth any number of lives, for bitter hatred and rage had long since replaced the sense of duty that had once governed them. Few of these warbands would survive the Horus Heresy, most driven to destruction by the new oaths they had sworn or overtaken by despair when all their efforts proved futile.Marauders - Shorn of honour and duty by the actions of their primarch and Warmaster Horus, some of the Legiones Astartes found a new truth in their own strength. For if the Warmaster might claim for himself an empire, then the mighty Space Marines could claim petty stellar kingdoms of their own. Pledged to no faction but their own greed and self-interest, these Astartes marauders raised dark and terrible fiefdoms among the forgotten shards of the Imperium. The noble truth of the Imperium was quickly forgotten and replaced with the rule of might, that the strong take for themselves what they saw as their due and the weak languish in servitude and suffering. Operating as pirates and raiders, these forces could not stand against a true army in open battle, but proved a persistent thorn in the side of those warlords fighting the great conflicts of the Horus Heresy. Preying on isolated outposts and vulnerable supply convoys, these warriors struck only where they perceived weakness before fleeing to their hidden domains, leaving behind them only ruin and destruction. Indeed many of these petty kingdoms would persist into the campaigns of the Great Scouring and beyond, as Blackshield warbands plunged remote sectors into a nightmare from which they could not escape, cut off and lost to the Imperium for centuries in the wake of the Horus Heresy.Atavists - Among the strangest of those phenomena that would be labelled "Blackshields" were those Space Marine warbands who, when faced with the bitter truth of the Imperium's collapse, chose denial over rage. Such warriors returned to the nameless storm-grey armour of the Great Crusade's first days, the time before any of the primarchs were reunited with the Space Marine Legions when all the Legions had been as one. Abandoning the insanity of the Horus Heresy, they turned once more to the task of conquest, seeking out the last empty corners of the galaxy to spread the Emperor's Imperial Truth. They fought only for their own delusional goals, heeding no emissary of the Warmaster or Emperor, and indeed would turn their blades upon any that dared hinder their private crusades. Unlike many other Blackshield warbands, these groups often retained the forms and titles of the Great Crusade, even if they had not the numbers or the panoply to match. In battle they fought in the old style, in rank and square, as they had during the Great Crusade, and eschewed all the modern trappings of the Imperium. Of all their kind, these warriors found little favour among the factions of the Horus Heresy, save as fodder for the guns of their enemies. Most would be lost, yet, in the last days of the Scouring, there exist scattered records of new realms incorporated into the Imperium, their conquerors clad in blank grey armour not used by the armies of the Imperium in centuriesDamned - The most terrible of all those that wore the title of Blackshield were those that chose to embrace that which the Emperor had once forbidden. Many heinous technologies and fearsome psychic abominations had been sealed away by the Emperor, kept safe by the threat of His wrath should any be foolish enough to unleash them. Yet, with the outbreak of Horus' rebellion, there remained none to ensure such terrors remained lost. Whether driven by desperation, self-consuming hatred or simple madness, some warriors took up these forbidden tools to destroy their enemies. Even the worst fanatics of the Traitor Legions and the most ardent defenders of the Emperor would not countenance the use of such deviant tools, and those who would turn to them were cast out, lest they drag down others in their madness. These abominations included weapons capable of terrible destruction to both friend or foe, as well as the corruption of body and soul. They were weapons, not of last resort, but of mutual annihilation, those that would serve only to see the Imperium dragged down into ruin and madness, with nothing left for the victors to rule over. From xenos arms of maddening construction to psychic powers long forbidden, and even the horrific techno-heresy of mutagenic cloning or the Silica Animus, some branded Blackshields would turn to any means to press their grudges. These bitter experiments would all end in disaster, some swiftly consuming those foolish enough to awaken them, while the most unfortunate would linger in torment for standard years laying waste to many isolated worlds before finally being annihilated.