 Of what these fallen sons are now, of what their betrayal brought them, and how power and pride mutilate nobility, but then anger would darken my words and hide the truth that you, my lords, so crave, I will not pretend to understand the reasons that drove my brothers down the path to ruin, that is for others to tell. Instead, I will seek to remind my lords of what these warriors once were, and so show the height from which they fell. It has been oft remarked by chroniclers of ages past that all wars begin with a single shot fired. The first bark of the first firearm to be discharged in either rage, in defence, or in betrayal. It is a pleasing narrative device that allows the human brain to grasp what is never, ever a simple occurrence. Rare is it that war is driven by a series of clear and concise motivations. Even should it appear so upon the surface, scratch that utter layer away, and you will find beneath the murky depths of forces social, economic, ideological, religious, and many, many more besides, all of whom powering two or more sides towards conflict. It takes work, rigorous applications of scholarship, education, learning, ability, and patience to construct a moving image of what truly leads to a war. Your humblest servant has previously attempted to do so, insofar as one can, dwelling as one does in a millennium benighted, using a mind ever besieged by the tendrils of insidious insanity. The Horus heresy is a conflict so large, so calamitous, so all-consuming that even today the walls of this palace within which I am privileged to dwell yet retain the scars they took from the guns of the traitors. This planet, this holy terra, counts as its foundations of its hive cities the dust of metropolis's yet more ancient demolished in the fires of the 16th Primarch's ambitions. Our imperium, wroughts from without and within, a juggernaut of an empire sustained merely through sheer inertia. We are born of heresy, all of us, the impact of the truest betrayal in human history continuing to reverberate 10,000 years later. When Horus Lupacal and his eight brothers brought all human progress to a crashing halt, humanity died in those years. That age of darkness we will never recover. Imperium endures, but it will never rise again. It is a gasp for air stretched out over thousands of years. The future is hopeless. It is broken. There is nothing left. And if this long, slow death were to have a first shot, the opening salvo in a war that sundered a species, upon a single world was it heard. No then, that this is a record of the beginning of a war that claimed the lives of uncountable trillions, of a day that sealed the fate of humanity forever more. A record of the Istvan III atrocity and the beginning of the Horus heresy. Located in the northern reaches of the Ultima segmentum, the Istvan system was a small but for the region relatively important celestial body. Containing not one but two worlds capable of sustaining human life, the system had been settled in the depths of the dark age of technology. Tens of millennia before the rise of the emperor upon Terra. The presence of these worlds on ancient stellar cartographical charts led to the region being marked for survey by the scout flotillas and rogue trader expeditions that ran ahead of the emperor's great crusade. And all signs pointed to the continued survival of humanity upon these worlds. Having been somehow spared the depravities of the age of strife, Istvan had seemingly maintained an advanced industrialized society, albeit one seemingly without either the capability or will to mount spaceflight missions outside of their solar system. The reunion between Imperium and Istvanian was not uncommon during the great crusade unfortunately fraught. The auto-Catholic culture that had endured the millennia of old night was one steeped in mysticism, one that thus reacted with dismay and defiance to early entreaties from the Imperium, which of course demanded the renunciation of all spirituality and the immediate cessation of all religious practices, all in accordance with the emperor's secular imperial truth. As with all instances of such defiance, hostilities were inevitable. The emperor and the Imperium's offer was binary. Priority was given to the system's capture, given the size of its human population, the location in an otherwise empty northern tracts of Ultima segmentum, as well as a potential wealth of its industrial base. It was an ideal staging ground for future crusade pushes out into the galactic north, not to mention its value as a sectoral hub in centuries to come. Excessive collateral damage was actively argued against by the war council. Any losses of infrastructure or population would damage the Imperium's prize. Accordingly, the assignment for its capture was granted to the 19th Legion Ravenguard and their Primarch, Corvus Corax, who had recently concluded operations in a relatively nearby volume. With the surgical precision the Legion was famed for, the Ravenguard struck from Istvan's planetary knight, seizing key points in the capital of Kry Vanak, roughly translated as Coral City. Within hours, before the sun had even crested the proto-Hives boundaries, the Senate that had ruled Istvan for centuries was a bombed-out ruin. All of its magistrates that had defied the Emperor's offer were either captured or dead. Pockets of resistance to the Ravenguard were swiftly dispatched, Corax following the orders to avoid collateral damage to the letter. Defiance guttered out. Compliance was achieved, and relatively bloodlessly. Istvan, like thousands of worlds before it, joined the Imperium unwillingly, but quietly, as off-world Imperial Army garrisons arrived to police the new colony and the Ravenguard departed to bring similar fates to some other far off world. The records of compliance, a form of after-action post-mortem report required by the Imperial Regime for all military engagements undertaken on human worlds, was filed by the 19th Legion quite promptly. The report made no reference of any esoteric or external influence upon the world, its population or its ruling regime. Nothing xenos, malefic, or psychic. The potential retention of religiosity was highlighted, with acknowledgement that the few violent holdouts were zealous devotees not only of the culture's primary faith, but sects and cults marginalised by mainstream Istvanian society and dogma. It was noted that many of these saw the downfall of the ruling regime as a sign of its inherent weakness and corruption, that the ideological vacuum created by official dogma's collapse could potentially lead to opportunistic growth by these cults, should they choose not to heed the Imperial truth. All of this was, of course, a problem now for the compliance regime, not the Legion as it started. Converting the population was the work of Imperial iterators, many of whom were now ceded amongst the Istvanians to convert them to the secular light of the Emperor's writ. As this was taking place, the Coral City was selected as the Imperial planet's capital, to allow for a symbolic transition of rulership. The shell of the presenter's palace was raised anew, as an Imperial cast from Fortress, to house its garrison, alongside which a new starport was constructed by Imperial Army pioneer corps and the adepts of the Mechanicum of Mars. Given that the system had required force to affect compliance, Imperial policy dictated the governorship be handed to internal personnel, rather than any local body. The man selected was Vardis Praal, formally a major of the 11th Lastron Rifles, who transitioned out of active service and into the political sphere as a career bureaucrat in the court of Ultima's segmentum. Given his experience in both the military and political wings of the Imperial regime, Praal was officially considered a safe pair of hands, to guide what was intended to be an important linchpin of future development in the system's local volume. Early records of said development prove that the faith of the Imperium was rewarded in Praal's reforms. Istvan flourished under his governance, becoming a peaceful and prosperous developing Imperial world, an almost model example of how to deliver compliance to a previously defiant human population. This was, of course, not to last. Several years into Praal's reign, conditions in the warp in Istvan's local region began to grade. It is not uncommon for the Imperium to develop squalls or storms, quite the opposite, but typically they do not last for more than weeks or months local planetary time. In the case of the Istvanian sphere, the storms lasted for years. The system had always been isolated in terms of galactic distance from other worlds. During the Age of Strife, it needed no outside connections nor desired them. Now, with Imperial rulers, the severance of that vital offworld connection was to prove incredibly challenging. Supplies rarely arrived. Many of the ships were simply forced to turn back rather than brave the tumult of the warp. Reports on the status of the system would only reach the Administratum upon Terra after many months, and often only fifth or sixth hand from a rogue tradership. All of them spoke of rising instability, of civil disorder, of Imperial iterators murdered by crowds of fanatics. Praal had apparently chosen to meet this fervour by ordering the complete destruction of cultural works deemed religiously tainted, as well as a devilishion of several ancient sites of mystic significance. The reasoning it was said was to break the subtle cultural hold the old faith of Istvan continued to hold over the populace, but reports did not say whether or not this had been successful. All that could be corroborated was that the cults mentioned in the Raven Guards after action report persisted, and that the most dangerous amongst them were being led by individuals bearing a title steeped in Istvanian mythology, the Gothic translation of which was rendered as war singers. Istvan quietly slipped out of all contact with the imperial, with Praal being trusted to get the situation under control, and matters of more pressing logistical concern diverting the Administratum's attention. It was not until six years after the last official word from the system had been heard that, by chance, a single patrol ship of the 14th Legion Deathguard, on its way out of Neogeddon, intercepted fragments of an astropathic transmission. The ship's own astropath was rendered near Catatonic by the information they received in their dreamfuge. Istvan III was in open rebellion. Vardis Praal had fallen and was leading the revolt himself. He had become corrupted by the religion of the world, had become a mutant, had become a ciker, or both. The coral city was drowning in blood. All non-believers would eventually be put to death, and an imperial world would now be cast down by the religious fanatics that rose like vermin from its sewers. Such an event could simply not be countenanced. Some who heard it blanched at the very idea. An imperial world, a compliant world? In rebellion? Such a thing simply did not occur within the boundaries of the emperor's light. These individuals were, of course, unaware of the long history of sedition that occurred during the Great Crusade. The examples were not many, it must be clarified, but they did occur. The lack of official acknowledgement of them was, of course, entirely to plan. None defied the word of the emperor, or the manifest destiny of the imperium to rule every world within the galaxy. Certainly, none lived to tell of it, and their stories never made it to anything even remotely approximating greater awareness. Recidivism on compliant worlds was put down with maximum force, swiftly and thoroughly. What was perhaps unique about the Istvan system was the scale. Billions of humans lived within the system, and it seemed now that open rebellion had been the case for years. Word of this had not yet leaked beyond the information obtained by the death guard, and none within the imperium's various bodies, who were privy to it, would see it go any further. The stain knowledge of such an uprising would cause upon the Great Crusade was unacceptable, lest it breed sedition elsewhere. Introducing the idea that the emperor could be defied? Impossible. Worse still, the appointed imperial governor was the figurehead of this defiance. The crimes of Istvan, and of Pral, demanded the swiftest of all responses, and the most merciless of all punishments. When the information reached the course of Horus Lupacal, 16th Primarch, Jeansire of the Sons of Horus Astartes legion, and reigning warmaster of the Imperium in his father's stead, his was a fury most righteous. Pral would pay dearly for this outrage, declared Lupacal, vowing to make a bloody example of the governor, and the people of Istvan for their truculency. This was, of course, barely a hint of what lay within the coils of the warmaster's true plans. As any student of history will be no doubt aware, the warmaster Horus had by now fallen under the thrall of the primordial annihilator, the so-called Dark Pantheon of the Chaos Gods. The process of the Primarch's corruption had been a long and serpentine one, the tendrils of the Dark Gods infecting Lupacal's ego from without, while the resentments for the course of his life, for the course of the Imperium, festered within. Your most humble servant has previously attempted where possible to chart the course of this personal downfall, records of which may be perused by Acolytes should they so wish. But suffice it to say, by the time the news of Istvan reached his ears, Horus was totally resolved upon his course of betrayal, and he was far from alone in this. Behind him, proverbially speaking, was the primarch Lorgar Aurelion of the 17th Legion word-bearers, whose own fall to the gods had taken place many years before his brother, and his legion wholly committed to their new deities. Entreaties, pacts, and deals most foul, had already been sealed with the lords of the 20th Legion Alpha Legion, 4th Legion Iron Warriors, 8th Legion Night Lords, Alphaeus, Pertorabo, and Conrad Curse respectively. Curse was at this point in his history all but renegade to the Imperium, having ordered the destruction of his erstwhile homeworld Nostramo before taking his legion into the Deep Void and almost severing all communication from the Imperium. Pertorabo, similarly, had wrought in his rage great suffering on the people of his world of Olympia, embittered as he was by an ego bruised from centuries of perceived injustices and mistreatment at the hands of his brothers and his father. Of the motivations of Alphaeus Omegaon, well, those can only be gassed out by chronicles such as mine. Suffice it to say, the serpentine lord of the 20th was never one to do anything by whim. These legions, and lorgars, were, thanks to the Warmaster's efforts, involved in campaigns in precisely the galactic reaches they were needed by him, but their time would come soon. More immediately, Horus' attentions were turned to the mustering of the 14th legion Deathguard, 12th legion World Eaters, and 3rd legion Emperor's Children, all of whom had been ordered to gather by his side. Counted amongst this muster were the Lord's Mortarian and Angron of the 14th and the 12th. Fulgrim, the Primarch of the Emperor's Children, had been dispatched on a mission of utmost importance to Horus personally, but in his stead was represented by Lord Commander Eidolon of the 3rd. These three, as with all the brothers Horus counted upon, shared the Warmaster's grievances with their father, although for deeply personal and idiosyncratic reasons of their own. Mortarian, for example, had grown disgusted with what he saw as the rank hypocrisy of the Emperor, as well as perhaps his own hypocrisy for serving a ruler he saw both as a tyrant and a sorcerer a witch, similar in too many respects to those he had spent his early life overthrowing on Barbarus. Fulgrim's desire for perfection in all things had devolved into a twisted obsession, aided in no small part by the eldritch influence of a curious sword he had obtained during the pregation of the Xenos Lair. Angron's hatred of his father had been a cancer in his souls since their first encounter, and his decision to follow Horus had perhaps been one of the easiest the traitor sons of the Emperor had made. In total, almost half the surviving sons of the Emperor had pledged to the banner of Horus. Of the others, well, the machinations of the Warmaster were far-reaching indeed. Magnus the Red, the Crimson King of the 15th Legion Thousand Sons, had fallen months previously in conflict with his brother Leman Russ of the 6th Legion. The burning of Prospero, as the battle had become known, was a direct result of Magnus' defiance of the Emperor's laws, it is true, but the death of the Primarch had not been explicitly the intent of the Master of Mankind. That Magnus had fallen, removing one of the most powerful of the Primarchs from the proverbial board, may or may not have been the direct result of Horus' intercepting of Leman Russ' capture orders. But regardless it had played into his hands very well. Not only were the Thousand Sons no longer a consideration in the grand scheme, the wolves of Russ had also been badly mauled by the battle, sustaining heavy casualties and dramatically reducing the threat they posed to the Warmaster's plans. Lupacow knew many of his brothers would simply never turn to his side, nor see his vision for the Imperium, and so had spent quite some time ensuring they would be in no position to challenge him once his heresy was revealed. The Lion of the First Legion Dark Angels, inscrutable and iron-clad loyal, first-born son of the Emperor, had been diverted to the far Galactic West by the Warmaster's orders. The Blood Angels, the Ninth Legion, and their sire, the Great Angel Sanguinius, had disappeared in the Cygnus Cluster, pursuing a mission on, yes, Horus' wishes. The Thirteenth Legion Ultramarines were preparing a muster in full at Calth, Pristine Jewel World within their Legion realm of Ultramar, the Primarch, Rebut Gulliman, having been issued instructions to await the arrival of Lorgar and the word-bearers, that they might heal their fractious relationship through campaigning against a nearby Orcoid Empire. The Seventh Legion Imperial Fists and Fifth Legion White Scars were beyond the grasp of Horus, but neither were of a special consideration for the Warmaster at this time. The Fists and their Primarch, Rogaldorn, were stationed in their near-totality upon Terra, acting as Praetorians for the Throne World. The White Scars and their elusive Primarch, Jagatai Khan, were primarily grouped in the long-running Chondax Campaign. The tendrils of Horus had crept into the Scars long before, through fraternal Warrior Lodge groups, and the Warmaster trusted that, in the event that the Legion did not sway to his side, their impact upon his plans could be mitigated. Finally, schemes for precisely what would befall the Eighteenth Legion Salamanders and Nineteenth Legion Ravenguard were already well in hand. And as for the Tenth Legion Iron Hands and their Lord Ferris Manus, the Warmaster trusted that Fulgrim's mission would go according to plan. Largest of the Loyalist Legions had been diverted or placed upon Courses of Doom. Others were accounted for, tracked, ensnared. This is of course not even accounting for the billions of Imperial military personnel, ships, war machines, and sundry other assets that fell under the scope of the Warmaster's command. Those you could count on were placed in favourable locales, granted access to the latest and most advanced technologies and gifted boons diverse. It was a game of literal regicide, only now played with pieces uncountable across a board unimaginably vast. By Horus' strings did the unwitting Imperium dance, and upon its shores was a storm unbelievable about to break. With the ignorance of the masses on his side, Horus' mission on Istvan appeared for all the world to be a punitive expedition that he described it as, although one that admittedly was in such a force as to stun any who read the disposition manifests. Sons of Horus, the Deathguard, the World Eaters, and the Emperor's children were all gathered in their near totality, all to take a single system. Such a force of arms had not been seen since the Olynor campaign, and that had been waged against the single greatest Xenos threat that the Imperium had encountered since the Rangdan Xenosides. To quell an uprising of civilian zealots, it was madness to think such an army was necessary. For a starty's legions was a force to conquer half a galaxy. Some whispered of the mad excessiveness of Horus' expedition, quietly wondering whether the ego of the still new Warmaster was demanding such ridiculous extravagance. But Lupercal remained firm that such an army was a necessity. It delivered in no uncertain terms the scope of the doom that would befall any other seditious populations. Should their defiance be so marked as to earn it? In total, some 200,000 startys were present, as well as significant quantities of the Exertus Imperialis regiments, Mechanicum Tagmata, Night Houses, and Titan God machines of the Ligio's Odax, Vulpa, and Mortis. And, at their head, three Primarchs, Horus, Mortarion, and Angron. Fulgrim's delay was notable but not unexpected, with Lord Commander Eidolon trusted by his Primarch, if few others, to serve correctly in his stead. A council was convened aboard Horus' flagship, the Vengeful Spirit, known to us largely thanks to scraps of surviving records from intrepid Imperial Remembrancers, who, for months now, had found themselves increasingly sidelined from the activities of Horus and the legions he counted as closest to him. Once they were welcome in his presence, now they were scorned. Ostensibly, this face-to-face meeting, breaking in Horus' new Lupercal's court, was a confluence of brothers and commanders to discuss strategy that would be undertaken once the fleet moved in system. In actuality, it is far more likely that within the walls of Horus' court, upon that day, the Warmaster assayed the commitment of his kin, and outlined precisely how they were to prepare for the betrayal that was at hand. And the Starty's Legion is not, as some may believe, a monolithic thing. Behind the iconography, the matching panoples, the shared genetic lineage, they remain composed of individuals. Individuals that, yes, are psychologically maimed as part of their genetic ascension, indoctrinated to comply to orders, and to serve a cause higher than their own quasi-immortal lives, but they are individuals nonetheless. Despite the direction their Genesires may elect to take a Legion in, the Primarchs were deeply aware that many Astartes under their command would balk at the idea of treachery, that their loyalties would remain with the Emperor, the Imperium, and the ideals of the Great Crusade. Since his own fall to the predations of the Dark Gods, Lorgar Oraelian had been at work to mitigate this. The fraternal warrior lodges were of his idea born. Ostensibly, a rankless meeting of brother Astartes, in actuality, they were perfect vectors for the poisonous ideology the 17th Primarch had embraced to seep into the Legion as Astartes. The embrace of the lodges by the Sons of Horus had been widespread, and they were met with varying degrees of success across other legions. Not only, indeed, did they serve to sway marines to the cause of the traitors, they additionally helped to identify those whose loyalty to the Emperor could not be counted upon, and would eventually supersede loyalty to Primarch. These Astartes would prove once the plans of the Warmaster and Kin were revealed a massive potential problem. It is believed that, at this Council of Primarchs, Horus unveiled to the assembled precisely how he intended to deal with that problem. East Van, despite the forces arrayed against it, was not expected to be a simple push-over campaign. What scraps of intelligence the Imperium had obtained spoke to a potentially malefic taint present in the rebellious populace. At the very least, the existence of enemy psychers was assured, those aforementioned war-singers. Such potential danger demanded a massive landing in arms. The Estevanians had never possessed much in the way of militarized spacecraft prior to the initial compliance action, and none remained in orbit to trouble Horus' fleet. A mass infantry drop, formed to appear for all intents as one of the Warmaster's famous spear-tip manoeuvres, would plunge via drop pod and flyer directly into the coral city, denying the villainous prowl any time to mount a unified planetary defense. The assault would be formed of infantry divisions drawn across all of the attendant legions. None would have much in the way of air cover, as the enemy possessed no airborne war machines, and there would be minimal armoured vehicle presence, save for some tanks and support vehicles drawn largely from the deathguard. What sparked curiosity for those selected for the initial wave was a manner in which it was seemingly being selected. There was little in the way of any sort of overall coherency. The startys were seemingly being plucked almost at random from units, and said units were often finding themselves assigned to a different consul, or captain, than they had previously been subordinate to. For whatever inscrutable reason, the Warmaster was playing fast and loose with the chain of command not only of his own sons of Horus, but three other legions besides. None of course had any authority to gain say this, had any even sought to. The Warmaster had absolute authority to conduct the affairs of all military assets under the imperial banner, and while the behavior appears to have raised eyebrows, nothing in the way of formal protest was lodged, even by legions at war to put it mildly quite prideful when conducting their internal affairs. There was one notable exception in this case. Tenth company captain of the Emperor's Children, Saul Tarvits. During the capture of an outlying Istvanian orbital outpost, Captain Tarvits, an exemplary line officer of the Third Legion, had witnessed what he believed was a display of antithical genetic modification amongst the senior staff of his Legion. Lord Commander Eidolon had, according to the journals of Tarvits, displayed some sort of biological enhancement that had allowed him to project sonic waves from his throat and mouth at such a rate and frequency as to destroy the bodies of the enemies arrayed against him. While the primarch of the Emperor's Children was not present, and the Lord Commander had ordered his silence upon the matter, Tarvits' suspicions about errant behavior amongst his Legion's Command Quadra led him to examine the assignments for the upcoming invasion, noting he himself had been assigned to the planetfall, but Lord Commander Eidolon was stationed to remain in orbit. In fact, very few senior staff from any Legion, and none of the primarchs, were included in the initial duty rosters, not even the bellicose angron of the world eaters. Tarvits was unsure as to why this was the case, especially in this instance that a warrior so egotistical and oft veined glorious as Lord Commander Eidolon was to be seemingly denied glory of leading from the front lines. Wishing to explore the matter deeper, but not to disrupt any sort of ongoing muster nor draw undue attention to himself, Tarvits requested leave to remain in orbit from one of the drop's most highly ranked Third Legion Astartes, the Contemptor Dreadnought Ancient Rylanor, who himself was preparing to lead the Emperor's Children in the drop. The suspicions of Saul Tarvits won Astartes amongst hundreds and hundreds of thousands. Would soon come to play a part in history, the man himself would scarcely have conceived possible. Four specific target zones had been highlighted for the invasion. The Precenters Palace was the primary objective, given that it was a seat of Imperial Governance and the Ancient Centre of Istvan's Theocracy, as well as the most likely location for the traitor Governor Prahl. The seizure of this was selected for the Emperor's Children. To the world eaters was given the responsibility of capturing a series of plazas adjoining the palace, where resistance was expected to be both heavy and projected to converge, allowing the Butchers of the 12th ample ability to indulge in their murderous skills. The Imperial constructed Western Bastions were selected as the Death Guards targets, with the goal of eradicating all those who dwelled within, and if capture was rendered impossible, that they be reduced to rubble. Finally, the Sons of Horus were tasked with the seizure of a massive Templum complex in the city's east. Known to the population as the Sirenhold, the historic buildings had been effectively abandoned during early Imperial colonization, mostly under the strict terms enforced by the iterators and by Prahl. But orbital reconnaissance had registered not only significant human presence in the complex, but exotic and unidentifiable energy readings too. If the degenerate religions of Istvan were here at work, this would appear to be the locus of both their arcane effort and their faith, making this perhaps the highest priority target of any invasion force, wishing to both break the military and spiritual hold of an enemy. Resistance at the Sirenhold was expected to be fierce and powerful. The War-Singers, the enemy Psykers spoken about in intelligence reports, had been encountered by Eidolon and the Emperor's children during their preliminary engagement in the system. The Psyker witches had reaped a toll upon the Astartes, but it was quite heavy before being brought down. Starports, typically selected as targets to allow for the landing of reinforcement and resupplies after an initial wave, were only marked as tertiary objectives. Clearly, the Warmaster expected a four-legion planetfall to succeed in crushing the enemy in near totality in one swift manoeuvre. When it came, the wrath of the Imperium hit Istvan with the force the world had never experienced, not even in those bloody days of early compliance. From orbit, the ground targets were hammered again and again by land strikes, a blizzard of blinding light beams that lasted, but for a brief moment until, riding upon the atmospheric hell their firing had wrought, a steel rain of drop pods plunged planetside. Resistance was far, far heavier than any projections had made. The Deathguard reportedly made first encounter with enemy forces, assaulting the western fortifications. The Istvanians were recognizable as imperial aligned, or at least their uniforms were. In aspect, they were peered now mad, mutilated things, almost inhuman incontinence, corrupted, it was assumed, by the sinister saucery of the War Singers, possibly even under some form of telepathic thrall. Certainly, they threw themselves at the attacking Astartes with what seemed like a complete lack of fear. Faced with the Deathguard, they not only turned Divisio Militaris' standard issue heavy weaponry against their attackers, but Basilisk artillery and Malkador heavy battle tanks, too. Against another Legion, this may have presented some challenge to overcome. To the Deathguard, it was yet another engagement where their famous fortitude would allow them to overcome. The 14th Legion's initial landing had brought them in so close to the Istvanian defences, as to deny their artillery even minimum range. The torrents of small arms fire and support weapons fire poured onto the Deathguard as they emerged from their drop pods, phased them not in the least. Wading through the storm that greeted them, Deathguard terminators and support squads camely and indefatigably targeted and demolished enemy bunkers. While the tactical squads of the legions swept their trenches with radiological and chemical weaponry, annihilating anything living with extreme prejudice. The fate of these bulwarks was fully sealed by the arrival of a demi-manipule of Titans from the Legio Mortis, whose god engines pulverized what was left to dust. The methodical sweeping of this sector was not, to put it mildly, replicated elsewhere. In the plazas of the central districts, the world eaters slaughtered their way through all that stood before them. Cohesion lost as a senseless melee filled the dense streets of the ancient city. Overhead, however, precision landing vectors identified by the 3rd Legion were followed to the T. Purple armored fliers of the Emperor's children circumnavigating the presenters palace seemingly effortlessly. Their assault ramps disgorging squads of Astartes in perfect formation, deep into the heart of the enemy's administration and defense. Finally, across the city, the Sons of Horus attack on the Sirenhold was being conducted with that legion's famed tenacity and ferocity. But the complex rapidly degenerated into a multi-story firefight of epic proportions. The entrenched its intervenions using the Labyrinthine Temple complex to punish the invaders for every step forward. It was here, in the Templum Fane of a culture thought consigned to history, that the war singers first made themselves known to Imperial forces. The enemy appeared to be wielding psychic forces to manipulate sound itself, utilizing it to fly through the air, surrounding themselves with Vibro fields to turn away small arms fire and, most devastatingly, project sonic force in such a concentration as to shatter the Ceramite power armor of the Legionnaires Astartes. Against the flesh within, even genhanced bone would turn to dust, modified flesh pulped to liquid by the songs of the war singers, whose presence additionally drove the half-mad armies of Istavan into a form of cultic euphoria, serving as potent idols in flesh to this malicious enemy. The arrival of the war singers upon the battlefield was felt not only by the Sons of Horus whom they were now arrayed against, but across the whole combat sphere. A psychosonic scream of shattering intensity was recorded city-wide, an auditory assault resistance to which was only possible thanks to Astartes' physiology and power armor, the autosensors of the latter throwing up sonic baffles against the sheer overwhelming force of the scream. Curiously, abominably, it affected the completely unaugmented and unprotected civilians of Istvan utterly differently. The populace, native, imperial, both regardless of alignment had been cowering from the inferno of war that had engulfed their world. With the arrival of this scream, they, as one, rose from their homes in hideouts and flung themselves at the invaders with a fanaticism unbridled. Without any care for their lives, with mouths frothing and eyes wild, the charge of the civilians took the Astartes by utter shock. The world-eaters, enmeshed within the civilian reaches of the city, felt it first. Dozens, then hundreds, then hundreds of thousands, a living tide of humans threw themselves at the chain axes and lady-eye of the 12th Legion. Never one to deny any a bloody death, the world-eaters happily obliged these thrall civilians, these mad things. But by sheer weight of numbers were being forced back to their landing zones. And Astartes, even alone, is easily a match for a hundred mortals. But isolated, surrounded by two hundred rabid hands clawing and seeking any crack in their ceramite, any makeshift weapon which might pierce it, even an Astartes may be brought down by a feckless swarm of corrupted minds. Bolters and support weapons ran dry. Even chain weapons became clogged with splintered bone and pulped viscera. The world-eaters were well accustomed to what, by the definition of any other age, would amount to war crimes most foul. But so rarely against an enemy that apparently did not care whether it lived or died. The battle, the slaughter, was hard fought. The day carried in large part thanks to the actions of two battle groups elsewhere. The first, led by 10th company captain Garvia Loken of the Sons of Horus, captured a bizarre corpse-clogged shrine at the heart of the siren hold, putting to death its war-singers. While in the center of the presenter's palace, Captain Lucius of the Emperor's Children battled the traitorous Vardus Praal in single combat. Warped beyond all recognition, his once proud imperial armor contorted with eldritch psychosonic weaponry and augmentations, Praal did indeed appear to be the leader of this corruptive cult. In desperate battle did Lucius slay him, the swordsman's peerless skill eventually overcoming Praal's warped sorcery. With the death of this magister thing, this once Praal, the hold of the psychic Gestalt appeared to break, no longer motivating the enemy upon Istvan. The abominable cacophony ceased, as did its hold on the population, many of whom appeared to fall catatonic or simply mad, thanks to its sudden dispersal. The rebellion, as it had been, was no longer functioning. The mutilated militia bereft of a motivating force were mopped up with ease, butchered as they wandered dumbstruck through the ruined city. It appeared that victory was won. Hard fought, yes, but the triumph of the Warmaster's retribution had been delivered. Or, so all those upon the surface believed, aboard the vengeful spirit, Horus, the Warmaster, had gathered in the main viewing gallery a curious audience, the remembrancers and exactors of the Imperium, the artists, poets, chroniclers, bureaucrats and aficiants attached to the 63rd expeditionary fleet, who had, since the fateful events with the Inter-Ex and upon Davon, been increasingly sidelined, treated with hostility by the Imperial military and Astartes aboard. Aware that such a summons from the Warmaster could not be ignored, the gathering was a large one. Almost every single civilian aboard was present, including the remembrancers Euphrates Keeler and Mercedes Olaton and iterator primus Kiril Sinderman, although these three were making all efforts to disguise their presence, going to issues Keeler was having with her status in the expedition's burgeoning cult of the Emperor Deified. Elsewhere in the fleet, Captain Saul Tarvitz had made a discovery that had, fundamentally, broken his world. He had uncovered orders that the weapons bays of the entire fleet had been ordered to be loaded with exterminatus-grade weaponry, specifically the monstrous life-eater virus. These were quite literally weapons with which worlds could be killed, an ultimate sanction hitherto reserved for planets deemed utterly lost to Xenos infestation. Nothing survived them. They were end times things, blasphemies created by the darkest minds of humanity and its most hateful epochs. Tarvitz drew the only conclusion available to him. Guided by his hearts, he commandeered a Thunderhawk gunship, knowing his message would never reach those on the soil of Istvan through conventional means. His escape was immediately noted and deemed a massive security breach by Lord Commander Eidolon, but Tarvitz's head start meant that only one ship lay within a possible intercept volume. The 14th Legion frigate, Eisenstein, under the command of 7th Company Captain Nathaniel Garrow. A Terran deathguard with a long and admirable service record, Garrow was known to Tarvitz and was now placed within an impossible situation, ordered by his Legion and others to fire upon his friend or to listen to the pleas that friend was making. Although communication logs of what was said between the two have been lost, it is confirmable by Garrow's later testimony that he ordered the Armada Imperialis fighters pursuing Tarvitz to be destroyed, refusing to fire on the Thunderhawk as it plunged planetside. It is safe to say that without this one decision, history itself may have taken an entirely different course. Abored the vengeful spirit, the gathered civilians beheld a figure they had not seen in months or years. Horace Lupercow, armored in night, bedecked in wolf pelt. Possessed, it seemed to many, of a conviction that went beyond even his typical resolve. In the viewports outside, inexorably, the battleships of the fleet were assuming a position over the planet below, an arrangement for all the world appearing to be for orbital bombardment. Like vast metallic cetaceans, the vengeful spirit, the Andronius, the Firebird, the Killing Star, the Conqueror, the War Child, the Gauntlet of spite, the indomitable Mill, all arrayed themselves. Horace bade the Remembrancers watch, his voice quiet yet reaching to all ends of the vast hall. They wished to see war, he declared. This is it. With that, droplets of light fell from the fleet, tiny bright pinpricks falling planetward in pure silence. The first of the virus bombs detonated above the Coral City itself. Air bursting munitions, they were intended to seed the atmospheres, upper and lower, with great clouds of their payload, and they did this within human uncanny precision. A single bomb could devastate a small world. Istvan was drenched in hundreds. The plumes of life-eater agents fused into the great clouds, racing outwards across the planet's atmospheric systems, carried upon the wind and air with terrifying speed. From orbit, it appeared for all the world as if stains were spreading across the pearl of the world. The assembled Remembrancers grew quiet as they beheld the sight. Some began to weep, softly. From so high above, it was all soundless. Planetside, the air was filled with screaming. Human, astartes, fauna, the virus claimed them all. The virus claimed everything living, from the mightiest transhuman warrior to the smallest bacterium. It was phenomenally, utterly effective, reducing anything organic to a rotting slurry in seconds as it ate at the fundamental molecules of all biological life. Everything that encountered it perished in pain that went beyond words, perhaps mercifully only for seconds, before they too were turned from a living thing into black necrotic tar. Where once a planet of billions had stood proudly dwelling within a diverse biosphere, all was rendered in minutes, a toxic choked hellscape of decaying matter. Grey desolation clad in gelatinous filth could now be seen from the skies as a corruption consumed the whole world. Six billion souls lost in minutes, weeping civilians aware, perhaps dully of what was happening, observed this all, catatonic in grief so that they did not notice the sons of Horus that entered the chamber now. The great crusade is over, Horus is said to have declared at that moment, to the horror of all the assembled. Perhaps they were now aware of what this meant, yet had such realization came it was too late for them. The Warmaster ordered their deaths at that moment. Artists, writers, historians, one almost wonders if the act was a symbolic one for him. The death of a culture only being born, wrought at his hand. His astartes carried out his will with ease, thousands of civilians that had gathered to hear the 16th Primarch speak were all dead in under a minute, torn to bloody shreds by bolters and chainswords of the Dugenez astartes. Horus did not even watch. Turning his back to the slaughter, he is said to have beheld the stained and ruined Istvan and issued the four words that changed the course of time itself. Let the galaxy burn. In the silence of the Void, a single land strike was born of the vengeful spirit. The eye-searing beam shot towards Istvan. It was not aimed at any sight in particular. It did not need to be. Its purpose was as match to kindling. The twisted, malicious genius of the life-eater virus was effectively as a two-stage weapon. In minutes, the virus could render all organic matter into slurry and miasma. A soup stewing amidst what remained of a world's biosphere. The sheer amount of flammable matter and gas this created was almost beyond comprehension. When it needed but a single spark. This was one that Horus had tossed upon the pyre. The firestorm that the land strike created was instantaneous. From the point of its impact, a circle of flame, is tsunami of destruction sped across the surface of Istvan. Its passage consumed in fire and ruined the remnants of what had once been life. The people, the animals, the plants all now fuel for an apocalyptic incineration of an entire world. The sheer atmosphere a chaos this created was another layer to the destruction. Deluges of megastorms and overpressure. Pounding what structures were left to dust and debris, even as the rocks they were made of were seared by flame. From orbit it appeared as if a new star was being birthed. An atmosphere of an entire world alive with dancing chaotic flame consumed by a corona of red and yellow and orange annihilation. Those in orbit observed Istvan burning in the heavens watching in morbid fascination or satisfaction at the unparalleled atrocity that is the death of an entire planet. Soon would the fires die down. The subatmospheric conflagrations guttering out as the organic slurry they had consumed was fully spent. An ash strewn orb now hung in the void, stripped in minutes of all life. The only sounds of the world now formed from the tortured atmosphere venting its pain in storms. Istvan was now a dead world and that dead world was a statement. Horace Lupercal, 16th Primarch, war master, had spat upon his oaths and his kinship. No longer was he the emperor's son and to this father's imperium would he visit the same destruction that this world had felt. Yet, for all the war master's infinite malice, for all his meticulous planning, there had not quite lain perfection. To indulge in a quote attributed to a lost ancient dramaturg, the best laid plans of rodents and regents oft go awry. The war master, for all his skills, all his plans, for all the power of his allies mundane and paramatural, could not control every single piece upon his game board. And because of the actions of the few, saw the potential of the virus bombing of Istvan III shrivel before his very eyes. The actions of two individuals have entered into legend because of it. Captain Saul Tarvitz of the Emperor's Children, and Captain Nathaniel Garrow of the Death Guard. As previously discussed, Tarvitz's discovery and subsequent flight to the planet below had been possible only thanks to the intervention of Garrow, and now, as the fires guttered out in the ruins of Istvan's atmosphere, the full scale of what these astarties had made possible was revealed. On the surface, all specks sweeps cried by initially confused and then horrified bridge officers, showed that out of the 100,000 or so astarties from the four assembled legions that had been committed to the first and only wave of the invasion, some 65 to 70% remained alive, all thanks to the warning delivered by Captain Tarvitz and relayed to all forces from his initial point of contact, believed to either be Garvia Loken of the Sons of Horus or Lucius of the Emperor's Children. These loyalists had scrambled for what shelter they could find, hastily ensconcing themselves within imperial constructed bunkers that yet remained standing after the furious battle that had only just petered out. Through this, through their armor's environmental protection, through their astarties physiology, through sheer, bloody luck, they had endured the viral cascade and firestorm both. They were not unscathed, as the account of Chrysos Morturg, appended to this record, clearly illustrates. The life eater virus was no respecter of even astarties genetic manipulation. Should their superlative power armor be even slightly breached, death came for them as sure as it found the unaugmented baseline humans it devoured. Yet, as stated, some two-thirds of the invasion had survived, and even now the communication channels exploded into activity. Rage filled the vox lines, curses spat skywards at the war master's fleet with an invective unprecedented for the act they had been subjected to had no like. This was betrayal, in the truest, most heinous sense, an act of such utter calculated malice that it is believed the minds of some astarties on Istvan simply broke at that moment. Madness, consuming them as their psychology, found itself unable to comprehend what their brothers, what their fathers had done to them. It would, of course, be remiss for one to not acknowledge the loyalists that yet remained in orbit, and one does not refer to Garrow alone. Despite the work of the war master, not every loyal astarties had been part of the initial drop, either through difficulty in assigning them to combat action without raising suspicion or errors in judgment on the part of the traitors or sundry other reasons. These astarties had watched the virus bombing unfold with absolute stunned horror, only to discover their erstwhile comrades behind them knives in hands. Though all no doubt fought as valiantly as such horrid perfidy would allow, they were cut off isolated and alone. This accumbed to their murders, with rage beating in their hearts. The same went for exertus imperialis troops, armada imperialis officers, and civilian humans. The massacre of the iterators and the remembrancers, that had previously been discussed, was one such extermination that played out across every ship in the fleet as traitor astarties exploded into sudden violence, targeting unaugmented humans marked for the slaughter. Such mere humans, however, did not all succumb to this betrayal. Many managed to flee their aggressors, using knowledge of the ships they served aboard to avoid death, and indeed inflict retribution upon their betrayers. Aboard the torpedo monitor du Croix, for instance, loyalists retained full control of their vessel, and turned its wrath upon the traitors as soon as it became clear precisely what was unfolding. In its spite, the du Croix managed to scupper several escort barks, and inflict significant damage on the battleship Killing Star, before the latter shot her to pieces. The Mechanicum Galeas, Xerxes 977, belonging to the fiercely independent tagma of the Ordo Reductor, refused all hails. She had joined the Warmaster's fleet as a latecomer, and was thus completely unaccounted for in the traitors' planning. Her wrath brought considerable pain to the warships that ran her down as she fled, unfortunately for her doom. Aboard the heavy cruiser Sunstone, the lifeguards of the Terran plenipotentiary, Duke Morticher, had managed to overcome a squad of Emperor's children sent to dispatch their charge, rushing the almost catatonic ambassador through the ship in a running battle that would eventually see them detonate the magazine of the vessel in defiance, tearing her apart amid ships and sending hull segments burning planet-side. History, naturally, concerns itself primarily with the tale of one ship, the heavy frigate Eisenstein, with Captain Garo in command. Aboard her were approximately 70 loyalist deathguards, survivors of a struggle that had apparently claimed the life of Second Great Company Captain Ignatius Grulgor in the latter's accidental unleashing of a life-eater virus payload aboard ship. Another party had sought refuge in her bays, too. Third Company Captain Iacton Cruz of the Sons of Horus, escorting the Remembrancers Euphrates Keeler and Mercedes Olaton and Iterator Primus Kiril Sinderman off the vengeful spirit, the warmaster's flagship. It was hardly much in the way of a force to resist the traitors in any terms. Given the accounts of the Remembrancers, of precisely what had taken place aboard the vengeful spirit, and the apocalypse they had just seen wrought on the planet below, Garo was under no uncertain terms, aware of the sheer danger he and his ship were in, and the sole option available to her. Run. The import of the message she and her crew carried could not be understated. Greta Calabrastes, in her post-heresy work, the now-prescribed Liberate Exinferis Essays Upon the Damnation of the Lost Nine, called the Flight of the Eisenstein one of the most singularly heroic acts in the history of humanity. While true scholarship must in its very nature stray away from considering actions of sole individuals as pivotal simply by their own virtues, it is undeniable that the courage of Nathaniel Garo was indeed a fulcrum around which the survival of the Imperium potentially turned. It was of course not without peril or struggle, having received no word from the typically British Grilgore. First Captain of the Deathguard, Callus Typhon, repeatedly hailed the Eisenstein from the battlecruiser Terminus Est, and when receiving no communication and noting her drive stacks were powering to full, moved to intercept the frigate. The relative proximity of the two made Garo's escape possible, but the Eisenstein was severely damaged by the batteries of Typhon's ship, the barrages killing the ship's astropath and mortally wounding its navigator. Breft of options, Garo ordered the Eisenstein to commit a blind warp jump as soon as the Mandeville Point's volume was reached, the frigate plunging into the Imitarium and beyond the reach of the pursuing Typhon. In István's orbit, matters for the traitors were only deteriorating. As a warmaster attempted to assess the current situation amidst a wave of retributive sabotage and defiance from loyalists still aboard his ships, the outlook spiralled wildly out of control due to the actions of one of his brothers. Angron, Primarch of the world leaders, ordered a landing in full, deploying near his entire legion to the surface in waves of gunship transports and drop pods, with himself roaring from the fore of it. A full fifty companies of the 12th legion slammed into the Ashen surface of István, as Horus, Mortarion and their assembled legion commanders could only look on in horror and rage. Angron's actions, of course, denied them the immediate and most potentially valuable course of action. With the bulk of the Horus-aligned world leaders now upon the planet's surface, not to mention their Primarch, the warmaster could simply not order a renewed orbital bombardment, lest he kill those he now counted as allies. His plans had been sullied by the survival of the loyalists, yes, but now they were actively and utterly thrown awry. On the surface, the Red Angel exploded forth from his drop pod, a hurricane of violence given vaguely human form. His destination had been the city plazas his legion had been assigned to capture, and where the majority of them had, against the odds, managed to survive the virus bombing. Leading the survivors was one Captain Erlen, who, along with his men, had been told by the Sons of Horus contingent under Captain Loken, that the virus cascade had actually been an Istvanian suicide weapon, a decision made by Loken for the sake of believability when time was at the essence. Having only just been told the truth before his Primarch's retribution force had made planetfall, Erlen was now the first to be presented with the faces of those he had called brother and father, the architects of his ruin and the ruin of his comrades. From what survivor testimony survives, it is believed that many of the loyalist world eaters simply descended into a rage of purest homicide, their minds sundered by the sheer scope of the betrayal. Two thousand loyalists faced four thousand traitors, and one Primarch. Both sides simply charged. It was heedless, senseless, an expression of rage untrammeled. There was no regard for tactics or formations, only the desire for both sides to end the other. The loyalists did not, one is sure, believe victory was a possibility, but one also does not believe that they even cared. Their fight was one driven by spite, that they may curse the names and bodies of those who had wronged them. Captain Erlen died this way, pinned to the ash by a dozen world eater astarties, and torn limb from limb even as his ruined, bloody face spat profanities upon those who butchered him. At his Primarch even noticed the death of a loyalist leader, Angron gave no sign. The gladiator lord of the 12th tore through his sons like a scythe through grain, an engine of slaughter shrugging off blade and bolt as if they were drops of rain. The nature of the clash meant it would only end when one side had put bloody death upon the other, and the presence of the Primarch as well as their numbers delivered this to the traitors. It is well done, the red angel is said to have declared, before bellowing to his men to spread out through the city and bring death to any they found. This, in so many ways, presaged the years that would become the age of darkness better than any of the violence that had preceded it. However minor in comparison to the battles that followed, this first explosion of intraliginary violence demonstrated to those that survived it, to those that witnessed it, precisely what lay in store for the galaxy in the years ahead. Bereft of the typical tempo of imperial-led engagements, the superiority of force, the potential for the sundering of morale, and all of these factors, all that remained was the unrestrained fury of the genetic monstrosities that are the estartes. Matched in temperament, armor, armaments, and augmentations, what remained now was simply two appallingly powerful forces smashing into each other with literally apocalyptic results. The breaking of the body superhuman was the only way to win an engagement. Soldiers that needed to be torn to shreds or blasted to atoms, lest their genetically enhanced physiology permit them to fight on. Even if one were to emerge victorious from such a battle, there is simply no way one could do so unscathed. The cynics amongst one's acolytes may argue that such a conflict had surely already taken place upon Prospero during its infamous burning. With the death of the Thousand Son's Legion that saw them clash with the estartes of the wolves that stalk the stars. I object in sterling terms to such reasoning. The burning of Prospero was a singular engagement between an estartes legion unlike any other, and all the mundane and arcane tools the emperor could muster to bring about their censure. It was a conflict between magister-psychor and feral-barbarian executioner, unique in so many ways. Upon the wastes of Istvan, for the first time in the history of the Imperium, the dread equanimity of the horse heresy was unveiled. Estartes versus Estartes. With Bolter in hand and Ladyus primed, transhuman juggernauts designed for nothing save conquest and slaughter, turning talents murderous to each other's mutual annihilation. It was the birth of an age of unremitting destruction. Above it all, in the strategic of the vengeful spirit, Horus watched and fumed. His brother had denied him the possibility of a cleaner, less costly ending to the atrocity he had committed, but even the powers of the Red Angel could not on their own overcome the loyalists that now remained alive. Firing any orbital weaponry with him in the crossfire was unthinkably risky. Never mind the potential it had for opening up yet another conflict, this time with the traitor world-eaters. With betrayal now a concept in the minds of the legion as Estartes, decisions had to be made carefully. The Warmaster could ill afford the loss of one of his traitorous brothers so soon in his rebellion, nor even the loss of many of the 12th Legion, nor even allow the loyalists still live any chance to fortify, co-olate and entrench themselves any more than they already had. Thus was his hand entirely forced. Victory would be forged from this chaos, of that the Warmaster was sure, even as he bridled at the cost it would no doubt extract. The general order was thusly sounded. Ground attack, full scale, all elements. The first to heed the call were the Emperor's children, with Lord Commander Eidolon at the van. Records of that legion show the Commander as being incensed at the actions of Captain Tarvits, smarting at such an open failure of his tenure in the eyes of the Warmaster, and it was no doubt a motivating factor in the speed with which the 3rd Legion deployed. The Percenters Palace was unsurprisingly their target. Eidolon ordered tightly organized columns to form as soon as the legion dismounted from their dropships, intending to move on the complex with as much speed as the 3rd could muster, assuming all therein would be a broken group of Emperor's children survivors, bereft of leadership. Overhead, Deathguard and Sons of Horus gunships ran reconnaissance flights, ensuring that legion seeker squads were deployed whenever these scout ships identified isolated or wounded bands of loyalists. There was, clearly, hope that these mop-up actions, punitively bloody and one-sided, would be all that was required beyond the central melee that the world-eaters were currently caught in. These notions were thoroughly disproved by Lord Commander Eidolon's advance. The shambolic defence the traitor had expected was anything but. It was, in fact, as coordinated and superlative as any the Emperor's children could mount. The glorious assault Eidolon has envisaged never occurred. His column came under punitively heavy fire, and was forced to retreat from what little advances they had made. The traitors had not even reached the outer walls of the palace, and in the wake of their departure, their only mark were dozens of burning, abandoned vehicles that had moments before been spearheading the advance. Further probing attempts made by 3rd Legion traitor infantry squads, aimed through the ruined breaches in outer defences, met with a similar fate, forced into an ignommonious withdrawal, as loyalist legionaries ambushed them or punished them from hastily but well-constructed readouts. Even the previously effective gunship runs, conducted by the 14th and 16th legions, diminished in efficacy rapidly. Loyalist survivors quickly identified the tactics being employed, hiding themselves in the morass of still-burning ruins at the sound of any inbound flights, the aspects of which were rendered nearly useless by the planet's tortured atmospherics. Indeed, the ruins were now the perfect place from where these loyalists could strike back at the storm birds and thunder hawks that ranged above them. Loosing las cannon bolts and crack missiles at the weak points they, having been well-experienced with these machines, knew all too well. A storm eagle gunship belonging to the Sons of Horus, arriving in the hangar deck of the cruiser Minotaur under all proper ident tags, immediately burst into suicidal fury, its crew of now-revealed loyalists bellowing that they would avenge the blood of Terra as they lashed out at the interior of the hangar with the fliers, las cannons, and multi-meltas, before ramming the craft into a line of rearming gunships next to ammunition hoppers. The resulting explosion killed a full company of traitor 16th legionaries both on the deck and in nearby corridors. All too rapidly for the traitors, the sheer familiarity that the loyalists had with their own ways of war was becoming bloodily apparent. Far from the broken husks the war master and his brethren had hoped to find, they were instead encountering a force armed with a tenacity and a fury born of utter and immediate hatred. Comnets and Vox authentication were rapidly scrambled following the incident aboard the Minotaur, but this only led to further confusion and disorganization on the side of the traitors as they attempted to overcome the logistical challenges. All the while, the death toll was rising exponentially in favor of the spurned loyalists. The advantage of loyalist parties was only growing planet side as night fell upon the Coral City. With the cooling of the planet's night side, the dust and debris that was choking the atmosphere began to settle, causing catastrophic hurricanes to emerge across the blasted wasteland Istvan now was. The winds churned massive quantities of still hot ash, pummeling anything that moved with torrents of burned once matter, even as volleys of lightning speared from the sky into the choked ruins. Flight was rendered an impossibility. The atmospheric interference was also proving devastating to the reliability of the Vox. The traitors were unable to bring their orbital and aerial superiority to bear in any capacity. And under the cover of the storms, all the War Masters subordinates knew that the loyalists would be moving throughout the ruins and underneath them, through the city's catacombs, linking up, establishing networks, consolidating what they had and organizing further. It appeared for all the world that the master stroke of Horus Luprachal was instead proving to be a colossal blunder. All the virus bombing of Istvan had actually achieved at this point was a genocide of billions of innocents and the provision for the Astartes survivors of a landscape that robbed any attackers of many to all of their advantages and granted massive boons to any that sought to defend us. The only issue the loyalists faced at this stage was resupplying themselves with ammunition. But such was the nature of the war that this event was not much of an issue. Their foes utilized the literal same weaponry they themselves bore. The Emperor's children under Eidolon had failed utterly with their maneuvers on that first day. The world eaters were scattered across swathes of the northern once city, an uncontrollable horde led by an uncontrollable commander. This, coupled with the storms, rendered another of Horus's advantages effectively moot. The titans of the legio mortis could not operate under conditions that they simply were not able to utilize their all-specs suites in, nor were their world killer weaponry able to annihilate the volumes that contained friendly assets. This was a situation that the traitors hoped would last days at most. It would in fact be weeks. One cannot recall at this point another example of warfare being undertaken in a planet previously subjected to exterminatus. The entire point of virus bombing is to annihilate all life and render the world unusable. Never before had any been called to actually fight over one. War was now one of bitter attrition. Typified by clashes of near indescribable fury fought face to face in ash swamped ruins at a squad by squad level. Reinforcements could only trickle in from orbit when the storms momentarily subsided, and on numerous occasions the legions in the void were forced to supply their ground forces with ammunition via drop pods, losing many in the process as the Hurricanes tore even these massively reinforced devices to pieces as they plunged to the planet below. loci of resistance emerged during these days. In the siren halt, twisted structure largely preserved from the hurricane force winds that beat upon its exterior, loyal members of the Sons of Horus Legion had defaced their sea green armor, dobbing it with ash to emulate their once gray panoply and reclaiming in their loyalty the original cognomen of the Legion, the Luna Wolves. Their leader, by circumstance and ability both, was Garvia Loken, formerly 10th company captain of the Sons of Horus and member of the Warmaster's Mornaval, a coterie of advisors. Consigned to his face on the surface for his staunch adherence to the ultimate ideals of the Great Crusade, Loken had risen from the fires of the Warmaster's wrath as the de facto general and warlord of the loyalist 16th on Istvan, coordinating their defense in the Siren Hold and utilizing every ounce of the Ganger tenacity the brutal Luna Wolves had been famed for. Attackers were forced to contend with foes that in the short span of time had mentally mapped the entirety of the Siren Hold's Labyrinthine corridors as if they were the mine tunnels of Cthonia. Under Loken's leadership, bands of traitors were cut off, isolated from their fellows, and brutally encircled. Once knives had been wet with blood, the defenders mobilized to elsewhere within the hold, a brutally effective method of mobile defense. Elsewhere, the presenter's palace yet held despite the fury of Lord Commander Eidolon. The resistance led by Saul Tarvitz and the Dreadnaught Ancient Rylanor, each stoking within the 3rd Legion Astartes present the exemplary elements of the Emperor's children's culture and ethics. The tactical excellence of the Legion was on full display in every engagement. The walls of the palace had been reinforced with heavy weaponry and vehicles recovered from Eidolon's initial abortive attacks and the hasty retreat subsequent to them. The palace's defense was further aided by the traitors being funneled into a narrow route of attack by roving bands of loyalist world eaters that preyed upon their flanks. Darkly, it appears that not all of these war bands were, however, loyalist. Traitor, world eaters, occasionally blooded themselves on traitor Emperor's children in their mindless fury. While the loyalist Astartes of the Sons of Horus and Emperor's children could be said to be enjoying some degree of success, the loyalist deathguard legionaries in the Istvanian Bunker Networks were facing a situation far more challenging. Despite being well supplied with not only arms and armaments brought with them from orbit in the initial wave, the 14th Legion being renowned for oversupplying their arms forces, they were caught between two exceptionally dangerous foes. From the inner city, Angron threw himself again and again at their lines, surrounded by bellowing blood-mad world eaters, purging tunnel after tunnel, heedless of any injury or casualty. From the wastes beyond the walls came the Red Angel's brother, the Deathguard's progenitor, Mortarion. The Primarch had come to the planet in the assault ship Omen, the 14th Legion relic of the Dark Age of Technology, and possibly unique across the entire Imperium, one which the Death Lord put to wicked use. Less a slave to Ego, that was Lord Commander Eidolon, Mortarion had the Omen's guns pummel the loyalist Deathguard positions, shattering outer trench networks as the ship disgorged a cargo of trudging traitor infantry, supported by super-heavy Spartan, Typhon, and fell-blade tanks. How well and how long the loyalists could resist this was entirely down to their personal mantle, but this is something that, to their credit, the 14th Legion has never lacked. If Mortarion wished for this hammer to be a quick victory, he was sorely disappointed. The battle for the trenches, as with the battle for the remainder of the city, was hampered significantly by inclement weather and the sheer tenacity of loyalist resistance. The storms would last for a full two solar months, months that saw traitor blood copiously shed for every square kilometer of rubble and ash they sought to expunge of the loyalist presence. It is by best estimate and testimony possible to establish that as many as 20,000 loyalist listarties perished during these weeks, but the death toll exacted upon the traitor attackers numbered easily twice that. The presenters' palace remained well defended by the emperor's children and, tangentially, world leaders' warbands, while Garvia Loken's luna wolves stayed off any major offensive on the siren hold. The deathguard were much harder pressed, but had at least been given the boon of rebellion from within the traitorous 14th's armor core. The crews of much of the heaviest siege armor, largely born of old Terran stock from the Legion, disobeyed direct orders from their Primarch, defecting to the loyalist side and turning their guns upon the traitor infantry. Mortarian's deathguard and Angron's world eaters both. The incident sundered the discipline for which the 14th were a watchword of, plunging the battle for the outer defenses into a confused morass of clashing, ceramite bodies as traitor fired upon traitor and loyalist attempted to exact whatever retribution the tumult provided them. Mortarian himself was said to have been burned by a plasma blast from a traitor predator battle tank in his own livery before he hacked it to pieces, ultimately forcing the Primarch to admit to a withdrawal and a regroup operation that brought the senseless debacle to an end and the loyalists a brief respite from the death lords relentless assault. The breaking of the storms, however, tightened the noose around the loyalists' necks. The traitors were now fully able to land reinforcements in quantity and especially the heavy armor and siege artillery sorely needed to provide them with a crucial strategic advantage they had previously lacked. Looted or liberated battle tanks from the Istvanian armories, typically Malkador line tanks, were pressed into service by the loyalists able to command them, but proved no match as whole squadrons of fell blade super heavies and Sikharan Venator tank hunters were now arrayed against them. The hammer of this armored support was fully wielded by the resurgent and furious Mortarian, pouring his legion strength against his erstwhile sons and finally shattering the majority of their positions. Forced to retreat into the deepest catacombs and bunkers, the loyalists' deathguard grimly waited for what they knew would soon find them, as the sound of Hades drill transports drew closer. This was mirrored elsewhere by what could only have been the word of Horus. Thirty companies of the 16th Legion, led by none other than First Captain Abaddon and the Jesteran Terminator Elite, made planetfall in the cities southwest, supported by Titan Manipals from the legios Mortis and Ordax, and finally making their presence known battle automata and tech magi from the so called new Mechanicum. As one author has put it, the mathematics of slaughter had now tilted, and it appeared that the hour of the traitors would soon be at hand. The first targets for the Titans of Mortis was to shatter the siege of the Precenter's Palace. Lord Commander Eidolon had to be in trying and failing to break the drudge of the stalemate there for two months, confounded every time by the fluid defense tactics of Sol Tarvits' loyalists. The walls had been designed to withstand significant damage and, thus far, done so admirably. None of the weaponry brought by the traitor Emperor's children had done much but scorch and pock the Rockcrete surface. However, the artifice of the Mechanicum that had raised them decades ago, had not nor had ever been required to, consider its capabilities against Titan-grade weaponry. The war horns of Mortis let forth a single blast, the only warning Eidolon's Third Legion would receive, before bringing the fury of the Calesia Titanica to bear. Arm-mounted volcano cannons pulled the power of suns directly from the god-engines' reactors, while carapace-mounted turbo-laser batteries took up the secondary refrain. Not since the firestorm of exterminatus had the city seen such destruction unleashed, and as with that world-killing incident the Astartes that bore its wrath could do not but weather the Cataclysm. The dust clouds kicked up by the weapon strikes were gigantic, plunging the palace into a darkness broken only by the screaming rage of volcano cannon fusillades. When it had cleared, the Princeps of Mortis had already known their work was complete by Osbeck's screeds. The curtain wall of the presenter's palace had been utterly demolished. Nothing save for jagged metal rebars and crushed masonry debris now stood before the traitors. Worse still, the dome of the inner precinct had sustained significant damage, its roof caving in under the rage of Mortis and the administrative building surrounding it falling in tandem. Into this breach, now poured the traitors, led not by Eidolon, but by Angron, surrounded by rabid squads of world eaters. The war master's fury was likewise meted out upon the siren hold. The aforementioned companies of the Sons of Horus led by Abaddon assaulted the Templum Fane from all vectors. Seistus assault rams pounded their way through its outer walls, while Legion assault squads howled downwards on jump packs from the holds of circling gunships, aiming for the sniper positions and gun emplacements of the loyal Lunawolves. There was no art history in the approach, just pure, bloody-minded, 16th Legion force, overwhelm with the fury unleashed from all angles. Abaddon himself led the Jasteran personally, secure within the holds of their black and red Spartan assault transports, the formation of which powered through the ruined city districts towards a siren hold in a brazenly full frontal assault. The sheer size of the Sons of Horus armoured spearhead denied the loyalists much opportunity to resist, and though Loken's wolves threw all possible heavy munitions against the oncoming juggernauts, the vast majority survived in time to discord their contents. Jasteran terminators and Catulan reaver squads, the cream of the Sons of Horus' first company. The loyalists lacked for everything, but courage, but against the ceramite storm courage mattered little. The defenders sought to sell their lives dearly. Many did just that, sundering the existences of their traitor brothers bitterly before being obliterated. Elsewhere, the emperor's children were facing a similarly brutal assault, the ferocity of the world eaters being pitched against their artistry, but unbeknownst to them, they were betrayed from within. Lucius, disaffected by what he saw as a lack of recognition for his actions during the planet kill, fuming at the heroism of Saul Tarvitz and seeing the position of the loyalists killed second company captain Solomon Demeter, defecting to the traitor side and opening up a vital route for the emperor's children and world eater attackers to press their advantage. In a personal duel with Tarvitz, Lucius was beaten by his former friend, only to escape back to the traitor's line. His position as 13th company captain restored, and his life to take on an altogether worse infamy. Of Tarvitz's fate, history is unclear. Given the situation within the presenter's palace, it is presumed that he sold his life alongside the best of the third legion, doing so long enough for the dreadnought ancient Rylanor to escape into the catacombs below, in possession of a device of significant value. Although that is a tale wholly for another record. In the ruin of the siren hold, at the end of all things, came a showdown of brothers. The Mornaval, Horace's famed four captain advisory coterie. It had been split by betrayal. Planetside was Garville Loken and second company captain Tariq Torgaden, while assaulting them from without were Abaddon and third company captain Little Horace Axeman. The four now met again, as the siren hold collapsed around them, kin facing kin, with naught but murder being a possible outcome. Torgaden, facing down Axeman, called doubt upon his one's brother's motives, stating, no matter the power of the warp, one must simply stand against it. The corruption of betrayal is said to have warred across Axeman's face, so similar in aspect to that of the warmaster. But ultimately, he chose the path of damnation, beheading Torgaden as the building collapsed around them. For Abaddon and Loken, their duel was no less intense, no less acrimonious, possessed of a ferocity of conviction by both parties rarely seen in the annals of history. Although there could only be one outcome. Perhaps underestimating his foe, Abaddon's early struggles in the duel were immediately learned from and counteracted. The brutal first captain, so peerless a fighter in the histories of the Legion as a startes, overcame his opponent with a brute force that was implacable as it was animalistic. Breaking the body and soul of Garvia Loken, Abaddon spat on the oes of kinship he once held, retreating from the collapsing siren hold to leave Loken buried under a tomb of what had been the 10th captain's most heroic hour. Across the city, the scene played out in a thousand different ways, traitor brother putting loyalist brother to death, often with far less honor than even Abaddon had offered Loken. The Mechanicum of the Warmaster and the Legion's destroyer corps bathed the last of the loyalist holdouts and phosphics, are called in the fury of the Titans. What remained was less a battle than now truly an extermination, detached from the now spent fury of the months that had preceded it, defined only by cold ruthlessness of genocidal slaughter. With bile most bitter, the traitors mopped up what few loyalists remained, before the Warmaster ordered a general withdrawal. Those loyal of the Legion were ash. What survivors remained, where there were any, did so with no hope of survival upon the ash and rock they were now confined to, nor to serve as any threat to the Warmaster's intentions. Thus were the final weapons of the Istvan atrocity fired, not an Astartes bolter, nor the horrific virus bombs, but the mundane conventionality of ship-board batteries. The ruins of the Coral City were fully pulverized once more, from orbit, an almost petulant end to the grueling hell of the battle that had been. A last wipe-out action to ring the last drops of spite from a war now done, yet also only just beginning. Thus draws to a conclusion the tale of the Warmaster's opening gambit. A stunning failure by any military standards, yes, but one that, ultimately, blooded the legions involved wholly and utterly in the warfare that would come to define the Age of Darkness. There was much experience to be deigned in this first open conflict between Astartes. Many points of data for the new Mechanicum to scry, many stories of battle for the traitors to swap, many combat techniques to be drilled into Neophytes on just how best to kill another Space Marine. Each and every division of every legion present was utilized as soon as it was possible to. Porus spared none from the actions on Istvan, nor any weapon in his arsenal. Given to the predilections of his benefactors and the presence of Davenite cultists during the final stages of the battle, one wonders if some sort of arcane significance was made in those last hours. A pact or a devotional, born of and sealed in the gen-hanced blood of the fallen loyal. This one can only wonder to, and one shall not, at this point, lest my sanity suffer even more so under the weight of this senseless tragedy. For tragedy it was, and one not unique nor isolated. The contagion of this perfidious war was already spreading, prospero and fallen not months beforehand. Abroad across the stars, the Blood Angels Legion disappeared in the Cygnus Cluster, and the word-bearers made full wake to Calth for their muster but the ultramarines. In the depths of the warp, the heavy frigate Agenstein forged ahead with its message so utterly important. And the galaxy slept unknowing, unaware of the scale of the horror that would soon engulf it. The warmaster and his ships, meanwhile, slipped anchor, but not for Terra, not even for another system, but for a planet nearby. Istvan 5, for the telling of that tale, dearest Acolyte, I must rest, and face myself into chronicling. This age of darkness, our tale now charts, of course, into Ave Imperator. Gloria in Excelsis, Terra. Subscribe, comment, let me know your feedback, and as ever, thank you very much for watching.