Horst - The Gothic War: While the vast majority of the Imperium of Man's defences around the Eye of Terror Warp rift in the northwestern reaches of the galaxy are based in the area known as the Cadian Gate, there are many Imperial monitoring stations scattered throughout the Segmentum Obscurus. These outposts are constantly raided and attacked by the various forces of the Chaos Gods, but during the second century of the 41st Millennium the number of these assaults dramatically increased. The most important of these attacks that served as a prelude to the horrors that were soon to come was the assault on the Imperial watch station on the world of Arx. Due to its low strategic importance, Arx was inhabited by only a small garrison of the Astra Militarum which was tasked with protecting the few Tech-Adepts of the Adeptus Mechanicus who were needed to maintain and operate the station's observation equipment.Early in 139.M41, the Imperial Navy scout frigate Ascendance received a telepathic plea for help from the Arx station's elderly Astropath. The identity of the attackers was unknown and when reinforcements arrived a full four solar months later, there was no sign of the raiders. The Imperial Guardsmen stationed on the planet had been wiped out and their bodies had been horribly mutilated and left to be devoured by the wild dogs that were Arx's only real predators. The Inquisition sent one of its most experienced agents, Inquisitor Horst, to Arx to investigate the matter, but there was little evidence left for him to sift through.If Arx had been the only outpost so attacked at this time, the raid would have become just another unknown in a galaxy filled to bursting with enigmas. Yet, over the next three standard years a number of similar attacks were reported throughout the neighbouring star systems and then spread into the adjacent sectors. Inquisitor Horst suspected that some larger plot against the Imperium was in motion, yet he could find no evidence to support his well-honed instincts or identify the nature of the attackers, so he decided to watch and wait for this canny enemy of the Emperor to make their next move.In 140.M41, several Imperial patrol vessels made grisly discoveries in the Athena Sector. A number of Imperial merchant starships and warships, one of them an Emperor-class Battleship, were discovered to be drifting through the void uncontrolled. Upon being boarded, it was learned that the crews of all these starships were dead, their stinking, disease-ridden corpses strewn along corridors and control panels, some still manning their stations. Each starship also bore the scars of weapons fire and a brief space battle, as well as signs of being boarded, though none of the enemy dead could be found. Inquisitor Horst puzzled over these developments while his Acolytes and spies brought him more news. A rumour had spread among the vessels of the Imperial Navy in the Segmentum that the attacks were being carried out by an ancient Chaos warship called the Plagueclaw, a vessel whose diseased followers were dedicated body and soul to Nurgle, the Plague Lord, and had been attacking Imperial shipping for close to 4,000 Terran years. The infection of the decimated ships' crews and the reappearance of the Plagueclaw were no coincidences, a reality which became all the clearer when the Death Guard Traitor Legion, the Chaos Space Marines dedicated to Nurgle, sacked the Hive World of Morganghast. Horst became convinced that the Forces of Chaos were planning another massive incursion against the Imperium united as Chaos Undivided. The watchposts around the Cadian Gate were put on high alert and Imperial Navy warships from all over the Segmentum Obscurus were ordered to defend the space around Cadia.Whilst Inquisitor Horst investigated the Chaotic activity around Arx and its neighbouring star systems, events turned even more sinister in the Gothic Sector of the Segmentum Obscuras, 2,500 light years from Arx. The Navigators of the Navis Nobilite reported greater disturbances than usual within the Warp of the Gothic Sector with the incidence of Warp Storms increasing as the sidereal year wore on. On many worlds in the sector, this news was received with panic, a situation made even more precarious by several religious fanatics declaring that the Emperor was displeased and was sending Warp Storms to purge the sinful. A number of new hard-line religious sects formed, their adherents stricken with feelings of impending apocalypse. They were desperate for the Emperor's forgiveness and began to flagellate themselves and demand that their friends and neighbours purge themselves of all their sins and inequities in the sight of the God-Emperor. On many planets in the Gothic Sector these cults became very politically powerful, swelled by popular support to such a degree that the Ecclesiarchy (and often the planetary governments) could do nothing to stop the rampaging mobs of hysterical flagellants. As the religious hysteria spread, lynch mobs roamed hive cities and mining colonies alike seeking the allegedly impure. Impromptu burnings and hangings became common as the desperately fearful citizens threw themselves into a fervour of eschatological abandon, scouring their friends and loved ones to atone for real or imagined sins against the Emperor. Yet all was to no avail as the Warp continued to become more active, the frequency of Warp Storms and their intensity continuing to grow.Under the cover of this widespread paranoia and religious excess, secret cults and covens insinuated themselves into positions of power, subverting ever more people to their dark causes. Misguided followers of the Ruinous Powers openly proclaimed that Chaos would save humanity when the Emperor had turned from them. Thousands, even millions of desperate Imperial citizens were deluded by these false promises, flocking to these cults, and the Inquisition's Ordo Hereticus was hard-pressed to root out every Chaos Cultist, deviant, mutant and Heretic. To make matters worse, several Imperial Navy vessels were destroyed in dock by Plasma Reactor overloads and magazine explosions. Though official reports declared the incidents to be accidents, many believed the tales of sabotage and rebellion within the Navy's own ranks.While the Gothic Sector was being engulfed in anarchy, religious strife and confusion, Inquisitor Horst was searching for more clues to the plans of the Heretics. When he heard of a Chaotic attack on the Imperial world of Purgatory, he chose to accompany the investigating Imperial fleet. There was one thing which made Purgatory different from dozens of other Chaotic raids in the region -- the device known as the Hand of Darkness. Its existence was known only to a few of the most trusted members of the Inquisition, for the Hand of Darkness was an incredibly ancient alien artefact located deep beneath the planetary surface of Purgatory. All attempts by the Adeptus Mechanicus to discern its purpose had failed, yet the legends of other, older races like the Eldar spoke of the Hand of Darkness with horror and revulsion. It was widely believed to be a weapon of immense power. When Horst arrived on Purgatory, the Inquisitor's deepest fears had come true -- the Hand of Darkness had been taken. If the followers of Chaos learned how to activate the alien weapon, they would be able to unleash incredible destruction upon the defenders of the Imperium.Horst knew of another artefact connected to the Hand of Darkness in the old xenos myths. Called the Eye of Night, it was located on the Ratling planet of Ornsworld. As Horst sped towards that world on the fastest vessel he could commandeer, a report came in by astropathic message of an attack upon the Ratlings. A small force of Chaos Renegades had landed close to where the Eye was embedded in an ancient statue, worshipped as a God by the Ratlings in pre-Imperial times. After a brief skirmish, an Imperial Guard recruiting force stationed near to the Chaos forces' landing site had driven off the raid. However, a solar month later Chaos starships blockaded Ornsworld and a full-scale invasion began. The defenceless Ratlings stood no chance against the depraved Chaos Space Marines and the death toll reached into the millions as the hills and mountains of the world were scoured with fire and shells by the most potent followers of the Dark Gods. Tens of thousands of Ratlings were simply murdered outright as the Forces of Chaos carried out a purge genocidal in its intent and scale. Among the carnage, the Eye of Night was torn from its mounting and the thief slipped away from the planet. The Forces of Chaos now possessed both the Hand of Darkness and the Eye of Night and thus the potential power to overthrow the Imperium of Man. Inquisitor Horst desired only to know where the Forces of Chaos would strike next.Horst did not know at the time that the Despoiler had learned of the existence of the means to control the Blackstone Fortresses -- the Hand of Darkness and the Eye of Night -- from the ancient crone Moriana, once an intimate of the Emperor Himself during the Great Crusade and an ally of the founders of the Inquisition. Determined to resurrect the Emperor in His mortal form after the end of the Horus Heresy, she had fallen to darkness over the millennia, and now acted for reasons known only to her.The old Inquisitor began compiling scattered reports of unusual activity in an ever-widening area and learned of the Warp disruptions plaguing the Gothic Sector. As he headed for the region, more reports came in of sightings of Chaotic starships in the region, reinforcing the notion that the Gothic Sector was the target of Chaos' next incursion. A solar month after Horst arrived in the sector in 142.M41, a cataclysmic shockwave passed through the Warp. The resulting massive Warp Storm engulfed the Gothic Sector in swirling tempests of Warp energy, cutting the sector off from trade or astropathic communication with the rest of the Imperium. The defenders of the Gothic Sector would face the darkness that was to come utterly alone -- the Gothic War had begun.Soon after, as the Forces of Chaos under the command of the Warmaster of Chaos, Abaddon the Despoiler, launched the massive offensive that was the Despoiler's 12th Black Crusade upon the worlds of the Gothic Sector, Abaddon unleashed the power of his Planet Killer for the first time upon the Cardinal World of Savaven. The planet and all of its 14 billion souls were destroyed in but an instant, as well as the secret Inquisitorial fortress that had existed beneath the many cathedrals of the Ecclesiarchy world -- a fortress that had served as host to Horst while he was present in the sector. Centuries later, the resurrected Primarch Roboute Guilliman would muse that Abaddon's choice of Savaven for the demonstration of his doomsday weapon's power had been no accident -- he had known of the existence of the Inquisition's fortress and of Horst's determination to stop him from using the stolen artefacts to claim the Blackstone Fortresses.Later in the war, the Imperials once more proved able to blunt Abaddon's offensive and forced him to retreat into the Eye of Terror, but not before he was able to take two of the Blackstone Fortresses with him. After the Battle of Schindelgheist, the Blackstone Fortresses in Abaddon's possession had been rendered all but ineffective, their power systems drained. Abaddon managed to escape into the Warp with two of them, after a lengthy chase to the edges of the Schindelgheist System and a jump into Warpspace dangerously near to the gravity well. The Imperial fleet closed in on the third, unleashing all of their weapons, although still to little effect. Finally, two Strike Cruisers from the Angels of Redemption Space Marine Chapter, combined with Shark Assault Boats from the Divine Right, boarded the isolated Blackstone in an attempt to recapture it. Ensign Goldwyn was part of the Imperial Navy's boarding party during this mission and he was the source of the reports which described what they discovered. There was no crew aboard the Fortress. The interior of the Fortress bore little resemblance to what the Imperial forces recognised and there was no sign at all of the modifications made by the Tech-priests, as if their intrusion had been totally expunged. The walls pulsed with energy, the surface of which had become a deep, veined black, the opposite of the harsh white-painted walls and corridors that had marked out the Fortress' interior during the time of Imperial control. The Imperials had been aboard for only an hour when a high-pitched whine filled the air and the walls became reddish in colour. The Imperials had no sooner left than, without warning, the Fortress suddenly began to break up and slowly shattered into thousands of fragments.At about the same time as the recaptured Blackstone Fortress destroyed itself, the other Fortresses across the Gothic Sector also self-destructed. We know now that the Fortresses under Abaddon's did not destroy themselves in a similar fashion, as the events of the 13th Black Crusade and the Terran Crusade would prove that the Chaos Warmaster had managed to maintain his grip upon the ancient engines of destruction. How or why the other remaining Blackstone Fortresses were obliterated remains a mystery. Inquisitor Horst believed that some things were just too dangerous to be allowed to exist and someone or something had decided that the Blackstone Fortresses were counted amongst that number.