- "The Eye of Terror is a realm of madness and despair, where skies weep blood, ancient stars burn in multi-coloured flares and the whims of the Dark Gods of Chaos hold sway. Synonymous with discord, terror, ancient secrets and insanity, no other place in the galaxy fills the mind with such dread and foreboding."
- — Extract from the Galaxia Daemonica Perpetua of Jerome [By order of Inquisitor Dalma, 453.M35]
The Eye of Terror (Ocularis Terribus in High Gothic) is a massive Warp Rift and permanent Warp Storm nearly twenty thousand light years across, a nexus of psychic energy and physical space-time where the Immaterium co-exists with realspace. It is the largest and most well-known Warp rift in the Milky Way Galaxy and is located at the rimward edge of the galaxy, to the galactic Northwest of Terra, in the Segmentum Obscurus. It is home to the largest concentration of the Forces of Chaos in realspace, including the Traitor Legions of Chaos Space Marines that fled from Terra after the end of the Horus Heresy. Incursions by Chaotic forces into the surrounding Imperial star systems are common, and the recent 13th Black Crusade launched in 999.M41 by Abaddon the Despoiler from within the Eye of Terror marked the greatest assault by the Forces of Chaos upon the Imperium of Man since the Heresy.
The Eye of Terror is not a naturally-occurring astronomical phenomenon. The Eye was created by the psychic shock wave that accompanied the birth of the fourth Chaos God Slaanesh, the Prince of Pleasure, during the Fall of the Eldar over 11,000 Terran years ago. The psychic shock of the birth was so great that it could not wholly be contained within the Warp, but spilled out into reality through the minds of the Eldar who died on their lost empire's homeworlds that now lie within the Eye of Terror and are known as the Crone Worlds. Consequently the Eye covers most of the region of the ancient Eldar empire. Other zones of overlap between the Warp and the physical universe were created at that time across the galaxy, but the Eye is the most significant and the largest of these Warp rifts. The Eye was originally designated a stellar anomaly known as Cygnus X-1 by the early astrographical Adepts of the Imperium of Man during the Great Crusade in the late 30th Millennium. It was Perturabo, the Primarch of the Iron Warriors Legion, who would give the Warp Rift its name as the Eye of Terror in the early days of the Horus Heresy. The existence of the Warp Rift had haunted Perturabo all his life, and his name for the anomaly was soon in use by the forces of Horus' Traitors and the Emperor of Mankind's Loyalists alike.
Though the reach of the Eye of Terror stretches across twenty-thousand light years of the galaxy in realspace, the region of space-time contained within the Eye constitutes its own reality, existing within both the material universe and the Empyrean dimension of the Warp. Although planets and star systems exist within the Eye, the standard physical laws of reality no longer fully apply. Time is a meaningless concept, and matter, thought and energy are indistinct and blurred with one another. The worlds within the Eye are known as Daemon Worlds and each planet constitutes its own bizarre sub-reality whose physical laws are shaped by whichever aspect of the dominant Chaos God is venerated by its inhabitants. At the very centre of the Eye lies the byssos, a hole in the fabric of reality through which raw Chaos energy pours out into the material universe. The Warp and realspace are indistinct and intermixed within the Eye, and the whole region is a maelstrom of psychic energy, impossible to navigate through normally using starships without a connection to the Dark Gods. Imperial starships avoid the area around the Eye for thousands of light years. Ships travelling too close to the Eye of Terror can be thrown far off-course - they can also be caught in temporal whirlpools which carry them backwards or forwards in time, or which trap them in temporal limbo forever. The Warp Storms that disturb the Eye are so intense that there is little point in even trying to steer a starship in a particular direction. The Chaos renegades and Chaos Space Marines who call the Eye of Terror home simply launch their starships into the swirling energies of the Warp, trusting fortune and the whims of the Ruinous Powers to carry them to their enemies. This makes Chaos attacks on the Imperium random, sudden and unpredictable, often occurring on worlds far across the galaxy from the Eye.
The Eye as a Refuge
The Eye offers a sanctuary to the worst of the Traitors and heretics forced to flee from Imperial justice. For the Traitor Legions of the Chaos Space Marines, the Eye of Terror has been their exile, sanctuary and safe haven for more than ten thousand standard years, from which they strike out at opportune, seemingly random, moments. The Eye is also a sanctuary for the most heretical renegades, fugitives of Imperial justice and traitors throughout the galaxy, and all are welcomed by the Forces of Chaos as fellow enemies of the Emperor of Mankind and the Imperium. Mortals within the Eye are constantly exposed to the effects of Chaos, becoming physically warped and mutated so their bodies come to reflect their flawed inner natures; the Chaos Space Marines of the Death Guard, for example, worship Nurgle, Chaos God of Death and Decay, so that their bodies become bloated and putrid, incubators for every form of plague and disease known in the universe.
The Cadian Gate
The Imperial world of Cadia lies nearest to the best-known stable gateway into the Eye; consequently it is the most fortified and militarized world in the Imperium, the first line of defence against Chaos incursions into realspace, thus earning the name the Cadian Gate. This area of stability is created by the network of Cadian Pylons that can be found throughout the region, instruments of Necron technology that were erected millions of years ago as part of that soulless race's great work to cut off realspace from all interaction with the Immaterium once and for all. For obvious reasons, starships exit through this gateway far more often than they enter it. The Warmaster of Chaos Undivided and leader of the Black Legion, Abaddon the Despoiler, led an attack through the Eye of Terror during a massive campaign in the 13th Black Crusade of 999.M41 that decided the fate of Cadia and many other Imperial star systems. Today, much of Cadia is currently occupied by the Forces of Chaos, but the Imperial Navy won control of the orbital space around the Cadia System and so the Chaos forces have found themselves trapped on the fortress world in a stalemate that leaves them still unable to break out into Imperial space.
Sectors and Sub-sectors surrounding the Eye of Terror
Due to the constant threat of raids and incursions, the Imperium's military forces are present in one way or another in almost every star system within 500 light years of the Eye. This military presence can range from small listening posts to heavily fortified frontier worlds.
- Belis Corona Sector - Belis Corona is the heart of the Imperium of Man's naval efforts and its orbital spacedocks are listed in von Heffman's Glorium Imperialis as one of the wonders of the Imperium. It is said that the entirety of Battlefleet Obscurus could dock in the vast orbital shipyards in orbit above Belis Corona.
- Medusa Sub-sector - The Medusa Sub-sector is famous as the homeworld of the Iron Hands Space Marines Chapter. Unlike many other parts of the Eye of Terror, life is hard and uncivilised barbarians inhabit many of the planets of the sub-sector.
- Scarus Sector - Scarus Sector is the most populous of all the sectors surrounding the Eye of Terror, with no less than six Hive Worlds which come together in trade, commerce, and mutual defence, all supported by numerous mining and agri-worlds. There are also two Forge Worlds, Nysa Stromolo and Mordax Prime, which supply the vast Scarus Defence Forces. It is said that 70% of the surface of Thracian Primaris, the capital world of the sector, is covered in hive cities.
- Scelus Sector
- Sentinel Sector
- Belial IV - Belial IV is an Eldar Crone World that lies within the Eye of Terror.
- Cadian Sector - The Cadian System of the Cadian Sector is possibly the most well-known star system near the Eye of Terror, with its 1st Imperial Guard Regiment having won many successful campaigns against Chaos and gaining wide recognition across the Imperium. Cadia's star system stands in the way of the only clear passage out of the Eye of Terror into the rest of Imperial space and so represents a fortress that the forces of Chaos must take if they are ever to topple the Imperium. Abaddon the Despoiler had attempted a campaign against the system almost ten thousand years ago during the First Black Crusade; after he was repelled by Imperial forces, Cadia was transformed into a fortress world against the sporadic attacks of Chaos forces in the Eye of Terror. Currently, much of Cadia remains under the control of Chaos as a result of Abaddon's 13th Black Crusade in 999.M41.
- Chinchare Sub-sector
- Nemesis Sub-sector
- Caliban Sub-sector
- Agripinaa Sector
Notable Planets of the Eye of Terror
- Altansar- Altansar is a small Eldar Craftworld that survived the Fall of the Eldar but was caught in the Eye of Terror following the birth of the Chaos God Slaanesh. Its only escapee was Phoenix Lord Maugan Ra. Ten thousand standard years later in the late 41st Millennium, Abaddon the Despoiler emerged from the insane reality of the Eye of Terror at the head of the 13th Black Crusade. Maugan Ra counterattacked the Eye of Terror to undertake a quest in search of the remains of his people; leaving a silvered trail of soulfire behind him, Maugan Ra eventually found the remains of his Craftworld, and discovered the Eldar of Altansar had indeed survived ten thousand Terran years within the Eye of Terror. Maugan Ra eventually guided the remnants of his Craftworld out of the Eye and against Abaddon's forces to deny the Despoiler ultimate victory. However, there was no celebration or welcome from the other Craftworlds, for Altansar is regarded with open suspicion and hostility, due to its long exposure to the corrupting influence of the Ruinous Powers within the Eye.
- Anathrax- Daemon World of Nurgle. During the Abyssal Crusade, the Iron Drakes Chapter made planetfall in force. Though they fought bravely, one by one they were brought low, surrendering their souls to Nurgle. Thus did the Iron Drakes become the Chaos Space Marines of the Grey Death, ready and willing to spread their plague across the stars.
- Belial IV - Belial IV was a Crone World within the Eye of Terror. During the Abyssal Crusade, the Brothers of the Anvil scoured the tumbled spires of the original Eldar empire, only to be brought to battle and eventually captured by the xenos Kabalites that searched the ancient planet for arcane artefacts. After a standard year of nightmarish ordeals in the arenas of Commorragh, the broken remains of the Brothers of the Anvil slaughtered their way back into realspace, where they killed every living thing they found.
- Bubonicus - Daemon World of Nurgle, ruled over by a former mortal Chaos Champion named Lothar, who was later transformed into the Daemon Prince known as Bubonicus.
- Drakassi - Daemon World of Khorne. This deadly world is wholly dedicated to the Blood God, its most notable feature being a sea of blood which covers the globe, connecting the various cities of the planet. Each city has its own arena where bloody gladiatorial games are held to honour Khorne in its own way. This world is lorded over by a diverse ruling class which includes daemons, barbarian chieftains, Amazon-like huntresses, Chaos Space Marines and mortal men who try to act like nobility. Their petty squabbling often results in open warfare, but they usually launch raids to other nearby worlds for slaves to fight in the games. Drakassi is lorded over by the supreme ruler known as Lord Ebondrake, a reptilian Daemon Prince, who commands the largest and greatest army on the planet and who sponsors the gladiatorial games.
- Durrell - Daemon World of Slaanesh.
- Eidolon - A notable Daemon World contested by the Ruinous Powers. This foul world is ruled by four warring Daemon Princes, who eternally fight for dominance of the contested planet. Blood Angels Captain Leonatos led his band of Exiles into the Eye of Terror and to the world of Eidolon, on a sacred Blood Quest, in order to recover the Blade Encarmine, a sacred sword and Chapter relic.
- Kathalon - A Daemon World of Khorne, this world is lorded over by the Bloodthirster Vangash'hagash the Ever-Bloody; his world is a great burning lake criss-crossed with arching bridges of brass and bone, over which the legions of Khorne and Tzeentch have fought for aeons.
- Maeleum - Daemon World within the Eye of Terror. For a time, Maeleum served as the first homeworld of the Sons of Horus Traitor Legion following the immediate end of the Horus Heresy in the early 31st Millennium. The XVI Legion built a massive fortress on the planet and entombed the corpse of their slain Warmaster Horus within it. However, not long after, the Eye of Terror Slave Wars erupted and the Emperor's Children Legion launched a devastating surprise assault on Maeleum, devastating the Sons of Horus' fortress and stealing Horus' corpse in an attempt by the corrupted Apothecary Fabius Bile to clone the dead Warmaster of Chaos and restore the fortunes of the Forces of Chaos in the wake of the Imperium's victory in the Horus Heresy.
- Medrengard - Medrengard is a Daemon World within the Eye that serves as the current homeworld of the Iron Warriors Traitor Legion. Located at the very entrance of the Eye of Terror, Medrengard is a world with a black sun and a white sky, its surface turned into a vast fortress, all trace of its original form lost under mountains of impossibly high towers, its core penetrated by plunging dungeons. Medrengard has been described as a bleak prison world where slaves toil endlessly for the glory of Perturabo. Great Chaos warships are tethered to the tallest fortress towers, wherein reside the Iron Warriors themselves.
- Oliensis - Oliensis is a Daemon World of Slaanesh which takes the form of a morbidly obese man curled into a foetal ball. During the Abyssal Crusade the Sentinels Chapter made planetfall and began to hunt down and exterminate goat-headed hedonists, but the cacophony of battle stirred Slaaneshi Noise Marines and soon the battle was joined. The raging conflict stirred the living planet itself, which swallowed the combatants into a large chasm. By the time they reemerged, the Sentinels were no longer recognisable, having been transformed into the Corpus Brethren.
- Plague Planet - The Plague Planet was a Daemon World of Nurgle. The Plague Planet is the home of the Death Guard Traitor Legion. Located at the entrance of the Eye of Terror, it is a world where disease is the norm and the viridian miasmic clouds that shroud the planet bring contagion and death. The Daemon Primarch Mortarion lords over the pestilent world, having shaped the planet to resemble his former homeworld of Barbarus. Its citizens cower in tiny villages, serving their supreme masters, the Traitor Marines of the Death Guard, who reside in mighty fortress citadels far above all of them. All spacecraft which succumb to plague are eventually drawn, through the Warp, to the Plague Planet, where they become part of the planet's Plague Fleets.
- Planet of the Sorcerers - The Planet of the Sorcerers is a Daemon World of Tzeentch and the home of the Thousand Sons Traitor Legion. Located deep in the Eye of Terror, the Planet of the Sorcerers is lorded over by the Daemon Primarch Magnus the Red. With the fall of his original homeworld of Prospero to the Space Wolves at the start of the Horus Heresy during the Scouring of Prospero, the Crimson King used his sorcerous powers in the final act of his pact with Tzeentch to transfer his beloved and infamous City of Light, Tizca, through the Warp from Prospero to a new planet. In this way, all of the precious (and heretical) knowledge hidden within Tizca's libraries that the Thousand Sons had gathered from all across the galaxy during the Great Crusade was preserved.
- Sicarus - Sicarus is a Daemon World of Chaos Undivided and the homeworld of the Word Bearers Traitor Legion. Sicarus is located somewhere deep within the Eye of Terror. From Sicarus, the veteran Dark Apostles of the XVII Legion who make up the ruling Dark Council watch over the Word Bearers Legion in their Primarch Lorgar's continued absence. The Word Bearers seek to orchestrate the corruption of the Imperium from within at the hands of the various Chaos Cults and witches' covens they sponsor across the galaxy. Beneath a roiling sky of fire and blood, Sicarus is a world completely covered by vast sprawling cathedrals, temples and monuments dedicated to the worship of the Ruinous Powers of Chaos.
- Temporia - Temporia is a Daemon World defined by a mind-bending contradiction of cog-plateaus, helical manufactoria and spiralling stairways that clank and span the planet's surface. Temporia is a corrupted Forge World controlled by the Warpsmith Valadrak, who constantly forges massive Daemon Engines for the various Chaos Space Marine warbands within the Eye. At the time of the Abyssal Crusade, this Dark Mechanicus Forge World was invaded by the Knights Excelsior Chapter. During their foray to the surface, the Knights Excelsior soon found themselves surrounded on all sides by massive Daemon Engines. The Space Marines hacked a path back to their dropships, but their escape was for naught, as the vile Warpsmith let loose an electricity-eating daemon fashioned from tortured Machine Spirits. The Knights Excelsior's dormant warships rebelled against them and their advanced wargear pulsed with static, and the Space Marines were overrun. They were snatched up in the claws of Temporia's Daemon Engines and thrust into the red-hot soul-forges of Valadrak's fortress. Less than a standard year later, the Renegade Space Marines known as the Magma Hounds were seen abroad in the Cadian System, their number almost double that of previous sightings.
- Ulthwé - A notable Eldar Craftworld, Ulthwé was caught in the pull of the Eye of Terror, where the Immaterium intersects with realspace. Due to this baleful proximity to the Eye, Ulthwé must be on constant high alert in case of attacks by the Forces of Chaos. Constant risk and warfare has hardened this Craftworld's citizens to hardship. Due to the lack of Aspect Warriors on the Craftworld, Ulthwé maintains a standing militia known as the Black Guardians, who are more skilled and better-trained than the Guardians of other Craftworlds.
- World of Immortal Sorrows - The poetically-named World of Immortal Sorrows is a Daemon World ruled over by a Daemon of Slaanesh called Elyssar'sirath. Once at the heart of the ancient Eldar civilisation, it is now a Crone World, where daemons of the Dark Prince of Chaos torment the souls of the fallen Eldar under the canopy of a great golden forest through which flow rivers made from the tears of Eldar children.
- Xana II - Xana II is a hellish Forge World which lies deep within the Eye of Terror. It is said to be a great stronghold of the Dark Mechanicus. Xana is believed to be a world wholly given over to daemon-machines and infernal industries, where mills grind flesh and suffering to make the insane visions of its nightmarish masters real, and countless millions are enslaved to work in a world-spanning network of labyrinthine forges, churning out an endless supply of weapons and armaments for the Traitor Legions' Long War. The masters of Xana are ruled by half-daemon machines themselves, and have long since left the shreds of their humanity behind and are beholden to none -- be they mortal or Chaos God. They sell or barter their unholy inventions and arms to the highest bidder, be they warlord, demagogue, sorcerer or Daemon Prince without favour, and their coin of exchange is always the same: new "raw material," the flesh and souls of slaves to feed Xana's endless hunger.
- Black Crusade: Core Rulebook (RPG), pp. 16, 25, 32, 49, 58, 263, 320, 322-323, 326, 334, 358
- Codex: Chaos Daemons (4th Edition), pg. 18
- Codex: Chaos Space Marines (6th Edition), pp. 5, 8, 11-15, 17, 20, 22-25, 32, 57, 63
- Codex: Chaos Space Marines (4th Edition), pp. 15, 17, 23-24
- Codex: Chaos Space Marines (3rd Edition, Revised Codex), pg. 8
- Codex: Chaos Space Marines (3rd Edition, 1st Codex), pp. 5-8, 44, 53
- Codex: Chaos (2nd Edition), pp. 8, 11-20, 26, 29, 48, 98
- Codex: Eye of Terror (3rd Edition), pp. 4-5, 8-9, 11-14, 24-25
- Dark Heresy: Blood of Martyrs (RPG), pg. 10
- Dark Heresy: Core Rulebook (RPG), pg. 221
- Dark Heresy: Daemon Hunter (RPG), pp. 8, 37, 106
- Dark Heresy: Disciples of the Dark Gods (RPG), pp. 145, 179
- Dark Heresy: The Radical's Handbook (RPG), pp. 113, 120
- Black Crusade:Core Rulebook (RPG), pg. 322
- Epic: Renegades (2nd Edition), pg. 49
- Imperial Armour Volume Six - The Siege of Vraks, Part Two, pg. 163
- Realms of Chaos: The Lost and the Damned, pp. 162-164
- Realms of Chaos: Slaves to Darkness, pp. 243-244
- The 13th Black Crusade (Background Book) by Andy Hoare, pp. 25, 50, 73, 85
- Warhammer 40,000 Rulebook (6th Edition), pp. 161, 168, 170, 186, 218, 222, 225, 228, 385
- Warhammer 40,000: Index Chaotica - Noise Marines (Digital Edition)
- The First Heretic (Novel) by Aaron Dembski-Bowden
- Angel Exterminatus (Novel) by Graham McNeill
- Eye of Terror (Novel) by Barrington J. Bayley
- Hammer of Daemons (Novel) by Ben Counter
- Treacheries of the Space Marines (Anthology) edited by Christian Dunn
- Battlefleet Gothic: The Galaxy of the 41st Millennium
- Eye of Terror Worldwide Campaign