The Eye of Night was an ancient artefact of unknown provenance linked to the xenos artefact named the Hand of Darkness originally located on the Ratling world of Ornsworld in the Gothic Sector. It was a multifaceted obsidian gem which emitted a cloaking haze of darkness and could unleash a beam of pure black energy capable of causing massive power failures or catastrophic internal damage to most forms of advanced technology.
The Eye of Night was stolen by the Forces of Chaos during the Gothic War and used by Abaddon the Despoiler to shut down the Imperial defences on three Blackstone Fortresses so that his troops could take control of them. The gem eventually made its way into the hands of the Chaos seer Moriana, who lost control of it to a Daemon Prince of Tzeentch. It was eventually recovered from this Daemon Prince's home, the tower known as the Pillar of Spite Fulfilled, on an unknown Daemon World in the Eye of Terror by the Inquisitor Katarinya Greyfax, a squad of Grey Knights and the undead Inquisitor Phaedus Falconet Horst in 999.M41. Greyfax returned it to the resurrected Primarch Roboute Guilliman, who believed it held clues as to how to close the Great Rift that had divided the Imperium of Man in half in the wake of the 13th Black Crusade and the fall of Cadia.
The Gothic War
While the Gothic Sector was being engulfed in anarchy, religious strife and confusion in the years immediately preceding the outbreak of the Gothic War, 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. Lieutenant Comton-Hawkins of the Astra Militarum recorded some of the atrocities caused by the Chaos forces, such as wiping out the small settlement of Esmerelda's Dale and bringing the side of the Great Belly mountain down, sweeping away seven towns and 82,000 Ratlings.
Among the carnage on Ornsworld, 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 three Blackstone Fortresses he had claimed control over 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.
Recovery of the Eye of Night
After the Gothic War ended, it appears that the Eye of Night fell once more into the possession of Moriana, who lost it in turn to an unnamed Daemon Prince of Tzeentch who dwelled within a tower on a Daemon World in the Eye of Terror called the Pillar of Fulfilled Spite. Inquisitor Horst eventually tracked the artefact down with the aid fo a squad of Grey Knights commanded by a Paladin named Bellicus, but proved unable to defeat the Daemon Prince. When at last Horst and Bellicus confronted the Daemon Prince of Tzeentch who called the Pillar home, the daemon succeeded in possessing Horst's body, forcing the Inquisitor to telepathically take over the body of Bellicus. Horst, now an animated undead being after Bellicus' death, returned to the ruins of an Imperial cathedral beneath the shattered Cardinal World of Savaven in the Gothic Sector that had been destroyed by Abaddon the Despoiler's Planet Killer during the Gothic War. He left a psychic beacon behind so that other psyker Inquisitors might locate him. He was eventually discovered by his fellow Inquisitor Katarinya Greyfax and revived in 999.M41, accompanying her on her own quest to recover the Eye of Night as an undead monstrosity wearing Bellicus' body and Paladin Aegis Armour. After Greyfax successfully tracked down and slew the Tzeentchian Daemon Prince with the aid of Moriana, destroying Horst's true body in the process, his spirit's hold on the material realm was seemingly broken, and Bellicus' body crumpled to the ground, cracking the skull within the Paladin's helm. Inside the broken skull, Greyfax discovered the Eye of Night -- Horst had unknowingly recovered it during his prior encounter with the Daemon Prince.
- Battlefleet Gothic Rulebook (Blue Book), pg. 93
- Codex Supplement - Traitor Legions (7th Edition), pg. 75
- Eye of Night (Audiobook) by Gav Thorpe