Battle of Calth - The Honour of Macragge: Two solar hours into the orbital battle, the Master of Vox of the Ultramarines flagship reported to Roboute Guilliman that the Word Bearers flagship, the Fidelitas Lex, had opened a lithocast-hailing channel. The Primarch of the Ultramarines stepped onto the holocaster platform at the centre of his bridge as the hooded figure of his brother Primarch Lorgar manifested before him in grainy hard-light. For perhaps the first time in his life, the famously measured Guilliman was lost to fury. He raged at his brother for his betrayal and swore to exact merciless vengeance. Guilliman denounced Lorgar's very sanity and swore that he and all his sons would be punished. But the Lorgar that listened to all of this with a smirk upon his lips and the remainder of his face hidden in shadow was not the being Guilliman had once known. No longer was Lorgar the cerebral seeker after truth who had debated the nature of the universe with his brother Magnus for days on end, nor was he the over-zealous son who had brought upon himself the censure of the father-Emperor he had decalred a god. Neither was Lorgar the chastened warrior who alone of all the Primarchs sought not conquest, but enlightenment. Here instead was a transcended being radiating a newfound self-assurance, as if he and he alone was party to knowledge still hidden from others, but which they would soon learn whether they willed it or not. No longer cowed or eclipsed before a more overtly purposeful or assured Primarch, Lorgar was the very essence of phlegmatic defiance.More shocking than Lorgar's manner, however, were the words he now spoke to Guilliman. With scornful derision, he informed the Lord of Ultramar that, contrary to Guilliman's assumptions, Lorgar's treachery was not vengeance for Monarchia and neither was it an isolated event. Rather, it was part of a long-planned scheme of impossible scope and ambition, and that no less than half of their brother Primarchs were complicit in it, including the greatest of their number, Horus. Three of their brother Primarchs, Lorgar claimed, were in fact already dead, a claim that history would reveal as erroneous, yet which he himself had every cause to make at that time. Guilliman was rendered speechless by the staggering hubris evident in Lorgar's words, yet he knew his brother spoke the truth, unpalatable as it may be. In that moment, he swore anew to end his brother's betrayal, even if it was the final act in his long and loyal service. Even if it was revealed as utterly contrary to sound tactics and sane strategy, Guilliman's sole intent at that moment was to hunt Lorgar down and slay his brother by his own hand.But it was not to be. Lorgar's hard-light avatar suddenly twisted, mutating into a monster torn from nightmare or the imagination of a madman. Guilliman ordered the hololith link terminated in disgust at what he dismissed as grotesque theatricality. Only then did it become evident that the hololithic signal lock had already been cut. The thing of eyes, teeth, tentacles, scales and unreal flesh standing in the centre of the bridge of the Macragge's Honour had transubstantiated from hololithic hard-light to corporeal flesh and the abomination was revealed to the horrified bridge crew and the enraged Primarch as all too real.An instant later, the entire bridge erupted in an explosion of phantasmagoric viscera, blowing out its armoured viewing dome and blasting its occupants into the void. At a stroke, the Ultramarines were bereft of their beloved Primarch and their beleaguered fleet had lost its flagship. What occurred next had no known precedent in the annals of the Great Crusade, for while the scions of the great Navigator Houses of Terra had some inkling of what lurked beyond, such knowledge was denied to all others, even the Legiones Astartes. The thing that had manifested on the bridge had exploded in a fountain of gore and the force of the detonation had breached the hull. The Primarch, who had been standing at the very eye of the storm, had been blown upwards and outwards through the breach in an instant, the writhing remains of the monster into which Lorgar's lithic avatar had transformed snaring his mighty form in a thrashing mass of spiralling pseudopods and motile shadow.The bridge crew were given no opportunity to save the Primarch, or even in most cases themselves. A dozen senior officers were swept up in the maelstrom of blood, debris and howling air, and blasted into the void in Guilliman's wake, vacuum snatching the screams from their throats. Shipmaster Zedoff, the veteran captain of the Macragge's Honour, was eviscerated by shards of armoured glass, his shredded body dragged from his command throne in a storm of ruined flesh. Even Space Marines had little chance of escaping the chaos, Chapter Master Vared casting away all void-breach protocol as he was witnessed attempting to aid his Primarch by launching himself upwards into the slipstream of blood and wreckage. He was never seen again. The First Chapter Master, Marius Gage, had been able to grasp hold of a railing at the moment of the breach and pulled himself along the tortured bridge towards the main portal, which was sealing off against the void even as he struggled towards it. Metres from the armoured hatch, Gage came across the grievously wounded Chapter Master Banzor and pulled his fellow Legion officer through the portal as the blast doors lowered. Banzor died soon after, but Gage had no chance to mourn him for the destruction on the bridge was but one torment being visited upon the Macragge's Honour. The entire conning tower was disintegrating around him and deafening howls of bestial insanity were flooding the corridors, accompanied by the screeching of tortured metal, the roar of escaping atmosphere and the wet screams of crew being slaughtered.Those few who survived the destruction on the bridge, almost exclusively Legiones Astartes, for mortal flesh was too fragile to withstand such hurts, were forced to flee downwards, pursued all the while by death as, deck by deck, the conning tower crumbled into the void. If any expected respite upon reaching the main body of the vessel, they were to be disappointed. The barrel-vaulted companionway which passed along the uppermost decks of the Macragge's Honour presented a scene ripped bloody and ragged from the worst excesses of Old Night. Crew hands were cut down, blood and severed limbs cast in all directions by things of warp-born shadow and searing empyreal fire. The more experienced warriors knew that catastrophic warp breach could bring on chronic hallucination and mass psychosis, while some were party to the theories that certain anti-life forms were able to exist in the shadowed depths of the Warp itself. But this was no warp breach, for the Macragge's Honour was in realspace.To the beleaguered defenders, it looked as if the entire ship had been boarded by creatures of no catalogued xeno-type at the very height of the battle the Word Bearers had initiated. Only the superior mental conditioning of the Legiones Astartes could bear such a weight of betrayal and horror, and many of the surviving officers reached the immediate conclusion that their traitorous brother Legion had unleashed some form of xenos-terror organism as yet another weapon in their perfidious arsenal. But the Ultramarines had no chance to mount a coordinated defence of the flagship, for the enemy's numbers were simply too great. Human crew were slaughtered, their minds overcome by primal terror at what they were witnessing. Lithe, horned creatures congealed of the roiling energies of warp space, whose skin glowed like lava and who carried wickedly barbed long swords, butchered those too stunned or too slow to flee. Other incarnated entities included bloated, plague-ridden corpse-things, one-eyed and drooling and using rusted cleavers to hew the helpless crew like meat on a butcher's block. Still others were deceptively mock-human, lithe and fleet of foot, possessed of viciously sharp claws that they used to sever and stab and gut foes who were stood helpless and enraptured at their approach. These and a thousand other insanities descended upon the flagship, until soon even the shattered chain of command that had survived the loss of the bridge was gone. It was as if a scene of ancient, apocalyptic mysticism was playing out, and the Space Marines of the XIIIth Legion were confronted with nightmarish foes against which the laws of reality themselves held no sway. Chaos, bloodshed and anarchy claimed the interior of the Macragge's Honour.The battle devolved into a bitter struggle for survival as individual warriors were cut off from their fellows and swept into the bowels of the vessel or else overwhelmed and slaughtered out of hand. First Chapter Master Gage and Antoli, so far as each knew the only Legion officers still alive, did what they could to restore sanity, ordering the crew to go to ground, to barricade themselves into whatever compartments they could while any and all Ultramarines, naval armsmen and soldiers of the Imperial Army were to rally together. Even this ostensibly straightforward order was almost impossible to enact. Wave after wave of horror flowed through the entire length of the Macragge's Honour, witnesses later describing how the angles of the bulkheads and the spaces between shadows were seen to wrinkle and fold in upon themselves before snapping taut once more to reveal savage wounds in the very skin of reality. It was through these wounds, which later would be described as "micro-rifts", that the creatures came.Across the ship, individual Legiones Astartes and naval officers fought bravely to repel the invaders. Falling back on long-established counter-incursion protocols, they ordered what responses they could. Entire sections were purged of breathable atmosphere or flooded with toxic gas, while others were plasma-scoured or subjected to worked. The creatures came on and ever on, impervious to effects that would have scoured the ship of any known life form. Such failures were compounded because the vessel's internal command and control systems had been crippled early in the betrayal, and with so many senior Ultramarines dead and lower-tier officers isolated from one another, the same mistakes were made over and over. The Ultramarines' famed ability to analyse any challenge and reason their way to victory broke down entirely, through no fault of their own.Worse still, the creatures were able to shrug off even the heaviest weight of fire from the Space Marines' bolters and other weapons. They swarmed unharmed through hails of fire to fall upon the defenders with otherworldly savagery. The creatures followed no perceivable strategy or logic, and it was apparent they had no objective but to shed blood. It would later be observed that they appeared more to be culling prey than fighting an opponent in any conventional sense, an observation many others would make before the end.