 When the fires of Horus' foul ambition had guttered out, and the righteous hatred of those loyal to the now-thrown-bound God-Emperor of mankind had scoured the taint of the traitors from the shattered remains of the Imperium, when the Astartes had once more set to uniting the galaxy under the true and just rule of Terra, they had changed almost beyond recognition. The Imperium was in turmoil, with every facet of it undergoing often radical reformation in the aftermath of the Emperor's ascension and our revelation of his divinity. The Astartes were no longer legions, but chapters, the sheer power of their old organizational structure deemed too much for any one being to wield in the aftermath of the heresy. The reforms of Rebut Gulliman, Primarch of the Thirteenth Legion Ultramarines, collected in the Codex Astartes, prescribed the new means by which the successors to the legacy of the legions would follow, encompassing everything from the chain of command to the disposition of companies to the reignments of the individual space marines. These, too, were changing. The galaxy was no less dangerous than it had been during the Great Crusade, but for this brave new world, new arms and armaments would be needed, to cast back the resurgent enemies of mankind, Xenos, mutant and now heretic. New arms and armaments would be needed. Know then, that this is a record of the panoply of war that bedecks the space marines of the Imperium, a history of the later power armor marks of the Adeptus Astartes. Despite the extreme scene placed upon aspects of Mechanicum and later Adeptus Mechanicus research and development during the dark, dark days of the Horus heresy, work on technological improvement did not cease entirely. If anything, the sheer hideous tragedy of the conflict had brought forth the type of ingenuity, often only found in the fires of war. The immediate pre-Heresy years had seen the widespread rollout of the Mark IV pattern of Astartes power armor, at that point in time the most advanced suit ever created at the hands of humanity, and heralded as the full and possibly final replacement for the still heavily utilized Mark II and Mark III suits. It was not, however, to be the final. The exigencies of the crusade led to numerous stopgap marks being created on the fly by legion tech marines and attached Mechanicum Tagmata, as well as the Mechanicum themselves, test piloting a whole new mark at the behest of the elements within the legion as Astartes, wishing for a lighter pattern of armor. These, historically, would come to be designated the Mark V and Mark VI patterns, heresy and corvus respectively, and a full account of them may be heard in my previous discourse upon the matter. While the Mark VI came close to full deployment to the legions that had requested it most, full-scale development was curtailed by the outbreak of the war. Necessity bred creativity, and while Mark VI armors were frequently utilized during these years, the Imperium was sorely in need of a full-scale change from the seemingly outdated Mark IV, which was proving highly difficult to maintain at full effectiveness in a war where supply lines were practically non-existent. The ultimate product of this was the Mark VII Aquila Armor, also known as the Imperator Mark, the pattern that would come to define the Imperial Space Marine for millennia to come. It is, technically speaking, a product of the Horus heresy, although so late in the conflict its impact is debatable to Historicors. Subsequent to the fall of Beta Garmin and the Titan Death, Root to Sol had been seized by the traitors. All within Imperial High Command knew of the inevitability of Horus' arrival in the skies of the Throne World, and by association the breaking of the Martian blockade. Since the fall of the Mechanicum of the Red Planet during the Death of Innocence, the combined might of the Seventh Legion Imperial Fist's fleet and the ships of Battlefleet Solar had kept Traitor Mars under constant void-borne siege. A canker at the heart of the Sol's system's defense, Mars was doomed to a seemingly inevitable recapture once fleet elements were required to be drawn back to Terran orbit. As such, as much research and development materials concerning Imperial arms and armaments had been transferred to the Manufactoria of the Throne World, and further science raids were mounted in the build-up to Horus' invasion. The newly reorganized Adeptus Mechanicus, true successor to the now dead Mechanicum, brought forth in those final days before the Great Siege, the Mark VII, an inheritor to the role of standard Legion power armor, and distributed to the legions present upon Terra as quickly and in as broad a capacity as possible, with the Imperial Fist receiving the largest quantities. The Mark VII represents a leap forward in power armor technology in many ways, but the primary goal was versatility. The heresy had led to many, many field marks, collectively known as the Mark V, emerging amongst the legions, formed of often crudely mismatched pieces from other suits welded and bonded together in manners sometimes barely functional. The primary Imperial requirement was for a suit that would be as adaptable as possible and backwards compatible with previous patterns. Owing to this, Mark VII pieces pair seamlessly with both the Mark IV and Mark VI armors. As such, many Astartes would simply seek to pair their newer armor with their preferred pieces of older variants. In many cases, the iconic beaked helmet of the Mark VI was favored over the snub-nosed, baleen-snouted Aquila patterns, as the older variant's aspect suite was considered far more better than the latter iteration. The Aquila's helmet did, however, feature the now distinctive Vox-Ogmitter grill, creating a far more robust atmospheric processing array intended to protect the wearer against the often extreme chem weaponry utilized by the traitors. Despite being produced with cheaper and more readily available materials, the Mark VII sacrificed nothing in the way of protection for its wearers, an aspect deemed literally essential given the horrific siege terror was set to endure. If anything, protection was increased by the Mark's now iconic chest plastron, designed to fully encase and protect the power cabling running across the marines torso in a way previous power armors had not been able to properly accomplish, having had to make the choice between heavy armor for greater defense or exposed cabling for greater maneuverability. Additionally, and absolutely a product of the later heresy years, this plastron now bore the Imperial Aquila. Previously, only the Third Legion Emperor's children had been granted the honor of bearing the personal sigil of the Emperor himself, but they had spat upon their oath to him, and it is said the Emperor now decreed that loyalty alone is to be cherished, granting all Astartes on Terra this previously unheard of right. This is likely apocryphal, as the Emperor most certainly had no capacity for the essentially whimsical fantasies during this particular part in history. Quite where the dispensation originated from is unknown, but those were dark days, and if some pious Mechanicus adept, or Astartes commander, is the one who made the decision, their hearts and intentions were no doubt as true as their loyalty. The Mark VII served the Astartes upon Terra admirably, offering them greater and more adaptable protection against the vast hordes of traitors they faced, many of whom took to the battlefield in battered, aged Mark II or III suits that had not seen a proper refit in a decade of constant warfare. In the aftermath of the heresy, the years of the scouring saw the Mark rolled out to fully equip all Astartes remaining within the Imperium. Many of the new successor chapters of the second founding were fully equipped with it from their earliest days, as Gulliman in his reforms sought to standardize the armory of this new adeptus Astartes as much as possible. The Mark VII's sheer versatility was an incredible boon to the Primarch's efforts, as it allowed for utilization in almost every battlefield role and Astartes could be asked to fulfill. Whereas in the Crusade, different legion squad formations would utilize different armor marks of baseline power armor for different tasks, such as breacher squads favoring Mark III iron armor, the Mark VII could fulfill all roles admirably, with the obvious exception of any better suited to terminator armor. Many chapters did, however, ensure to retain older patterns in their armories, but often these would serve simply ceremonial or honor positions. Being assigned to Astartes would one themselves the great privilege of bearing what were rapidly becoming relics of days and ideals long gone. Production of the Mark VII was rolled out to all remaining and old new forge worlds of the Adeptus Mechanicus, and production on all earlier marks, say for the more specialized Mark VI, gottered out until ceasing completely. The Mark VII has served the Adeptus Astartes for over 10,000 years. This is both a testament to the sheer versatility and durability of the design of this particular pattern, yes, but it is also a damning indictment of the path our Imperium has trod these many millennia. While the Adeptus Mechanicus has made technological strides in this time, defying those who would call them backwards to stagnant, one cannot say the same of the Imperium, which is all too eager to discard the pursuit of anything even approximating progress, in favor of ever more heavy-handed and reactionary paths. The Adeptus Astartes were founded to be independent in a large part, removed from the broader chains of command, by necessity of letting few wield the power they represent. The increasingly siloed forces of the Imperial military engine work in concert, yes, but lack the cohesion the texts of the great crusade Spikov when they relate of the combined arms of those heady days. Chapters are responsible for their own logistics and supplies, often forming quasi-feudal relationships with nearby Forge worlds. While these arrangements do suffice, they rarely do anything more than that. Development. Progress. These are words unknown. The Armoriums of these chapters are filled with suits often older than the chapters themselves. The Mark VII armor has become hereditary, passed from Astartes to Astartes, enduring modification for each new bearer, dutifully serving for century after century of unending conflict. It became a rare thing indeed for new suits to be manufactured, as the 41st millennium staggered to its close. Ironically, considering its initial years, the Mark VII became expensive and difficult to produce, as the decay of knowledge worsened and the state of the galaxy became ever more tenuous. As with many things in the Imperium, maintenance, rather than creation, became of paramount importance. The only update to the power armor line, during the Imperium's slow 10,000 year deterioration, was the advent of the Mark VIII errant armor. An iterative design, if ever there has been one, the Mark VIII has been argued by some as little more than a upgraded and heavily modified version of Aquila plate, although one believes it is worth its separate designation for a series of factors. It accounts for what some Astartes have pointed as the flaws inherent to that particular pattern, to make it easier to produce. Errant plate has even more reinforced chest armor, fully enclosing every last exposed piece of cabling. Supplementary armor was further added to protect ribbed flexible joints on the hips, and the ankles of the grieves have been adapted to provide a better range of movement. Its most distinguishing feature is the raised gorget designed to protect the wearer from stray hard rounds that might ricochet off the chest plating and damage the neck area. While this does defend the Astartes better than the previous iterations, the gorget causes significant issues with armor compatibility, as Mark VI Corvus Helms simply cannot be fitted with it, and Mark VIII Helms require heavy modification. Despite being extant for several thousand years, the Mark VIII is not in widespread use. The majority of chapters prefer to depend upon the workhorse of the Mark VII, as the cost and speed of manufacture the errant plate requires makes it ill-suited to widespread deployment. Its rarity and maintenance demands place additional strain on any who would add it to their armories, something many can ill afford, leading it to become something of a prestige suit, granted to veteran Astartes in a chapter in recognition of service in much the same way as the relic suits of the Mark II and Mark IV now are. The only force to make notably widespread use of this mark is the Deathwatch, the Astartes' manned chamber militant of the Inquisitions Ordosinos, capable, as they are, to command far more specialized resources and technology than the vast majority of Adeptus Astartes' chapters. Had it not been for recent events, the Mark VIII would likely have been the final iteration of Astartes' power armor ever to have been deployed, but fate, as it often does, had other plans. A Fall of Cadia, the Second Battle of Terra, the Return of the Primark, the Indomitus Crusade. These events and more have marked the need for a total paradigm shift within the Imperium and for once we are blessed with the leadership with which to accomplish this. By the writ of the reborn Gwylliman himself and the genius of the newly re-emerged Archmageus Bellisarius call, an entirely new form of Space Marine, the Primaris, Astartes, was born onto the Imperium and with them a radically overhauled armory that would help spearhead a new wave of Imperial expansion and conquest. To grant onto these newest of the Emperor's Holy Warriors, Call himself bent his efforts to a full new armor pattern, the Mark X. The suit is nothing short of a marvel. To some, it may be even borderline heretical in its technical brilliance. Stated to combine the versatility of the Mark VII Aquila, the more advanced aspects of the Mark IV and Mark VIII plates, the Mark X is a fully modular armor system capable of easily retrofitting for a variety of roles. Whereas the Mark VII was typified by its employment in all roles and Astartes would be called upon to serve, the Mark X can instead be adapted to fit a Primaris Marine's intended combat role. It is a line-wide series, variance of the same core system rather than actual different armor marks. Thus, Primaris intercessors, the strategic successor to Astartes tactical squads, are clad in Mark X Tacticus armor. The orbital drop troops of the Inceptor squads wear heavy jump pack equipped Mark X Gravis armor, allowing them to drop from planetary atmospheric shells into close fire support positions. Revert troops employ lighter Phobos Mark X plate for forward reconnaissance and covert operations, while the Mark X Omnis armor of the suppressor squads ridges the gap between Phobos and Tacticus capabilities. Primaris marines are an evolution in the capabilities of the Adeptus Astartes, designed to protect the Imperium from the terrible threats of the 42nd Millennium, and this is to be reflected in their panoply. Mark X armor carries with it capabilities in whatever variant that are intended to support this aim. All officers of any rank have inbuilt cogitator communicators in their van braces, and the queases of all variants contain multi-purpose socket ports for everything from drug stimulant injectors to dataport access cables. The Mark X's power pack is the most efficient of any armor mark yet, in keeping with the higher demands of the new system, but also more heavily armored to allow the Primaris Marine surety during combat. Due to this and heavier armor all around, the Mark X plate is not wearable by mainline Astartes, owing to the greater strength and speed required to utilize it to its full capabilities. In another break from the past, perhaps the one most marked, the outer Ceramite layers of the Mark X plate are ablative, designed to be the first layer to be stripped away by enemy fire and endure damage to protect what is underneath. In this way, it is disposable, in a word. This is reiterated by the modular nature of the Mark X itself, as a Primaris Marine can change and retrofit his suit to fulfill every combat role. The very concept of this is heresy to the chapters of the Astartes before the return of the Primark, where, as noted, the passage of Mark VI or Mark VIII or Mark VII plate was akin to the passing of relics down through the lineage of the chapter. That a suit can lose entire parts of itself, and then be immediately replaced by an identical system, is testament to this new Imperium that we are now a part of. The Primark's legendary practicality has no time for the quasi-religious veneration of ancient and outdated war gear perpetuated amongst the Adeptus Astartes. If an Astartes cannot fulfill their stated mission, the annihilation of the Imperium's enemies, with maximum efficiency, then that is a situation that needs rectification. The Mark X is a statement by Cole and Gulliman to the rest of the Imperium, an attempt to shake us out of our stagnation and resignation, and aid them in seizing a new era. One can but hope that they are successful. Ave Imperator, Gloria in Excelsis Terra. of my Patreon subscribers. If you'd like to help support the channel, head on over to patreon.com forward slash oculus imperia. And if you're looking to keep in touch with the channel, get regular updates, you can follow me on twitter, at buttstuffkaiju, or check us out on discord, a link will be in the description and on the channel page.