- "This is Cadia, you silly fool! Cadia! Right on the doorway of Chaos! Right in the heart of everything! The seepage of evil is so great, I have a hundred active cults to subdue every month! This place breeds recidivists like a pond breeds scum. This is Cadia! This is the Gate of the Eye! This is where the bloody work of the Inquisition is done!"
- — Inquisitor-General Neve
Cadia, officially known as Cadia Prime, was a terrestrial, Earth-like planet classified as both a Civilised World and as the Imperium of Man's most important Fortress World by the Administratum. It was the fourth world of the Cadian System, and its surface contained a wide variety of terrain types and ecosystems, including frozen tundras, temperate plains, wind-swept moors and the great native axel-tree forests. Cadia guarded the only known navigable route to and from the massive Warp rift known as the Eye of Terror, a passage called the Cadian Gate. The world's dangerous proximity to the Eye of Terror made it necessary for the people of Cadia to heavily fortify the planet. Cadia was always the first target of the Warmaster of Chaos Abaddon the Despoiler's Black Crusades. These were the massive assaults the Forces of Chaos launched every few Terran centuries from the Eye of Terror in an attempt to break out of the Cadia Gate and invade the Imperium proper as they did during the Horus Heresy.
Cadia's natural environment was much like Terra's millennia ago, with a large ocean that covered 70 percent of the planet's surface. The land mass of the world was divided between incredibly thick pine forests of axel-trees and vast glaciers. The planet was slightly cooler than most human-settled worlds but not to the point that it adversely affected growing conditions. Settled before the onset of the Age of Strife by a branch of humanity that eventually fell to the worship of the Chaos Gods and played a major role in the ultimate corruption of the Space Marine Legions, Cadia was re-settled sometime in the early 32nd Millennium by Loyalist humans of the Imperium.
The world's landscape was dotted by strange black monoliths of clear xenos origin called the Cadian Pylons. These devices were actually constructed by the Necrons millions of standard years ago to hold back the psychic energies of the Eye of Terror from the world, which was an ancient Necron military base during their war with the Old Ones.
The Cadian Pylons are what created the unusual area of realspace stability known as the Cadian Gate near the Eye of Terror that is unaffected by the constant Warp Storms that surround that Warp rift. Cadia's location directly adjacent to the dangerous Eye of Terror made it necessary for the people of Cadia to fortify the planet to an extent where almost the entire population lived in massive fortress-cities known locally as "Kasr." Thus Cadia had an odd mix of dense urban areas and vast open tundras and other natural landscapes unspoiled by the hand of Humanity.
Unfortunately, disaster struck at the climax of the 13th Black Crusade in 999.M41. Archmagos Dominus Belisarius Cawl, with the aid of the Necron Lord Trazyn the Infinite, had finally learned to use the Cadian Pylons to close the Eye of Terror once and for all. But Abaddon the Despoiler, enraged by the continued defiance of Cadia's people, gave up on his personal attempt to bring the Fortress World's defenders low with the activation of the pylons. Instead, he sent the bulk of the Blackstone Fortress Will of Eternity, badly damaged by the assault of the Imperial Fists' star fortress Phalanx, crashing into the surface of Cadia like an artificial meteor. This monstrous kinetic strike wiped out most of Cadia's defenders, destroyed the network of Cadian Pylons and tectonically destabilised the world. As the Warp and its foul denizens claimed the remains of the Fortress World, Lord Castellan Ursarkar E. Creed arranged an evacuation of the planet that saved 3 million of its citizens before the planet finally ripped itself apart -- though not before Creed himself mysteriously disappeared.
The fall of Cadia represented a once-unimaginable triumph for the servants of the Dark Gods, and the Eye of Terror began to slowly expand without limit, opening Abaddon the Despoiler's coveted Crimson Path to Terra and creating the Great Rift that divided the Imperium in half.
Yet among the few survivors of Cadia was a handful of Imperial heroes who had successfully escaped the destruction of the Fortress World with the aid of the newborn Aeldari faction known as the Ynnari. The combined forces fled through a Webway gate found on the ice moon of Klaisus in the Cadian System. Together, these Imperials -- the so-called Celestinian Crusade -- would forge an uneasy alliance with the enigmatic xenos that would offer a new hope for the servants of the Emperor in their fight against the waxing power of the Archenemy -- the resurrection of the Primarch Roboute Guilliman.
Some 40 standard years before the outbreak of the Horus Heresy, Cadia was a world inhabited by a primitive race of violet-eyed humans who worshipped the four Chaos Gods, probably a remnant of Mankind that had turned to the Ruinous Powers during the hardships of the Age of Strife. Prompted by the so-called Pilgrimage of the Primarch Lorgar of the Word Bearers Legion to discover whether or not the Gods once worshipped by adherents of the Old Faith of the Word Bearers' homeworld of Colchis actually existed, Lorgar journeyed with his Word Bearers Legion's Chapter of the Serrated Sun to what was then the fringes of known Imperial space as part of the 1301st Expeditionary Fleet of the Great Crusade. At this time, Lorgar had not yet fallen to Chaos, though he had turned against the Emperor of Mankind as a deity no longer worthy of his worship after the Emperor and the Ultramarines had personally humiliated him and the entire Word Bearers Legion on the world of Khur 43 standard years before the start of the Horus Heresy. The Emperor had come to Khur personally with Malcador the Sigillite after ordering the Ultramarines to destroy the Khurian city of Monarchia where the Emperor was worshipped as a God as a result of the teachings of the Word Bearers. He made his displeasure known to Lorgar about the Word Bearers spreading the religion of Emperor-worship to every world they brought into the Imperium, in direct contravention of the rationalist, atheist philosophy of the Imperial Truth. The Emperor forced the entire Legion to kneel against their will through the use of his psychic might and then explained that they were the only Astartes Legion to have failed his purpose on the Great Crusade. After this humiliation Lorgar, on the advice of his First Captain Kor Phaeron and the Word Bearers First Chaplain Erebus, decided to undertake a Pilgrimage to discover if the Gods worshipped by the ancient Old Faith of Colchis were real and worthy of the Word Bearers' faith and allegiance.
The Word Bearers were also accompanied on this Pilgrimage by 5 members of the Adeptus Custodes who had been set by the Emperor to watch over everything the Word Bearers did to prevent them from falling back into error once more. The 1301st Expeditionary Fleet exited the Warp near the largest Warp Storm in the universe, later known as the Eye of Terror. The Fleet's Master of Astropaths advised Lorgar that unusual "voices" in the Warp were heard in the vicinity of the great Warp rift, voices that spoke directly to the Primarch as well, the voices of the Chaos entities within the Immaterium.
The decision was made to hold orbit over Cadia and for the 1301st Fleet's elements to make planetfall on the unknown world, designated as 1301-12. The landing force was comprised of Imperial Army, Word Bearers, Adeptus Custodes and Legiones Cybernetica elements. The landing party, led by Lorgar, was greeted by a large number of barbaric human tribes, tribes described as "dressed in rags and wielding spears tipped by flint blades...yet they showed little fear." Most notable were the barbarians' purple eyes, which reflected the colour of the Eye of Terror itself in the spectrum of visible light. Despite the Custodian Vendatha's protests and request to execute the heathens, the Word Bearers approached the natives. A woman emerged from the crowd and addressed the Primarch directly, calling him Lorgar Aurelian and welcoming him to Cadia. This woman, the priestess Ingethel, would ultimately lead the Primarch down a path of spiritual enlightenment that actually marked the beginning of Lorgar's fall to heresy and Chaos. Later, Ingethel of Cadia would lead the 1301st Fleet's scout vessel Orfeo's Lament into the Eye of Terror and thus change the Word Bearers forever as they were exposed to the Ruinous Powers of Chaos and slowly corrupted, the first of the Legiones Astartes to worship the Chaos Gods and become Traitors to the Emperor. The Cadians, primitive as they were, used a language which was akin to the Word Bearers' own Colchisan tongue. Many traditions of the Word Bearers were mirrored by the culture of ancient Cadia, leading Lorgar to believe that the original settlers of both his own homeworld of Colchis and Cadia shared a common heritage.
Following the visits into the Eye of Terror, Lorgar ordered a cyclonic bombardment of the planet, wiping out the Cadians and leaving the planet abandoned, so none within the Imperium would know what had transpired there.
Following the Battle of Terra that ended the Horus Heresy with Horus' death and the interment of the Emperor of Mankind in the Golden Throne, the defeated Traitor Legions and their allied forces among the Imperial Army and the Dark Mechanicus fled from Terra. Some of the exhausted Loyalists rallied and gave chase, but most remained on Terra to consolidate their great victory over the Forces of Chaos. Many of the surviving Traitors were put to the sword, but the majority of the Traitor Legions escaped into the great Warp rift known as the Eye of Terror in the Segmentum Obscurus, a region of space where reality and the insanity of Chaos collide as the raw psychic energy of the Immaterium pours into real space-time.
Within the Eye of Terror, the Chaos Gods rule over uncounted numbers of planets, all warped to reflect their own dark aspects. It was there that the Traitor Legions found refuge, isolated from the rest of the galaxy by potent Warp Storms. Each of the planets within the Eye is a Daemon World, warped and twisted by the whims of the Ruinous Powers and the powerful Daemon Princes who rule over them in the Dark Gods' name. The Chaos Space Marines regrouped and nurtured their hatred of the Imperium, planning for the day when they would wreak a terrible vengeance on those who had defied them and their foul masters. Within the Eye time flows differently than in realspace. Those same Traitors who fought on Terra 10,000 standard years ago still fight today in the service of Chaos. They fight against each other to prove their supremacy and against the forces of the Imperium when the Warp Storms calm enough to allow them to emerge into Imperial space.
The Imperial sectors surrounding the Eye of Terror were heavily militarised to resist these frequent invasions and none more so than Cadia, the Imperial Fortress World that stands at the very mouth of the only stable navigational route leading out of the Eye of Terror, the dreaded Cadian Gate.
As a result of Abaddon the Despoiler's 1st Black Crusade in 781.M31, the planet's strategic location was deemed vital to the defence of the Imperium, and so, in the 32nd Millennium, Imperial colonists were despatched to resettle the world, becoming the ancestors of the present-day population of Cadians. Perhaps as a result of the Eye of Terror's proximity, this later population of Cadians also soon developed the unusual violet-coloured eyes that had marked the first human inhabitants of the planet.
The early defences of the newly resettled Cadia proved to be woefully inadequate. Its major cities were extremely vulnerable to enemy assault as they had been constructed in the traditional High Terran style, with broad, ordered avenues. Following the 2nd Black Crusade in 597.M32, sweeping changes were carried out worldwide to improve the planet's overall defensive capabilities, and massive fortifications were constructed across the world until the planet's cities had been rebuilt into their current form.
Cadia stands upon the only known reliable route out of the Eye of Terror and thus is one of the most strategically vital worlds in the entire Imperium of Man. There are other routes out of the Eye, but none are stable like the Cadian Gate and no military force of any true size can venture forth from the Eye without first passing through it. The exact reasons for the existence of this unusual region of stability is unknown, though many Magi of the Adeptus Mechanicus believe it is due to the presence of the famous Cadian Pylons. These mysterious black monoliths, now known to have been created by the Necrons millions of standard years ago to hold back the psychic influence of the Warp that was so feared by their C'tan masters, dot the landscape of Cadia. Their origins remained mysterious to the Imperium until the time of the 13th Black Crusade.
Cadia itself was a bleak, merciless and wind-blown planet, where only the strongest survived to adulthood and discipline was learned from the moment a babe took his or her first steps. Cold winds howled across wide, sundered plains where armies trained with live ammunition and every solar day not spent training was believed to be a day wasted. Every Cadian fortress-city, or "Kasr", was a massive citadel, with the streets and buildings fashioned with great tactical cunning by the finest military engineers and siege specialists of the Astra Militarum (Imperial Guard). Every Cadian was taught the skills of the warrior as soon as he or she could walk and Cadians were much sought after by commanders throughout the galaxy. Cadian military gear is considered top-rate and is used as the base standard for all Astra Militarum regiments. Such a world bred hardy and determined warriors and the Cadian Shock Trooper Regiments of the Astra Militarum have a well-deserved reputation for both honour and fighting spirit. From the earliest ages, Cadians were taught to field-strip a weapon with their eyes shut and tactical doctrine was memorised before basic literacy.
13th Black Crusade
- "The Chaos dogs cower before our guns. Gentlemen, let us take back what is ours."
- —Lord Castellan Ursarkar E. Creed of Cadia
In 999.M41, when Abaddon the Despoiler finally launched his 13th Black Crusade, the greatest Chaos assault on the Imperium since the Horus Heresy, the Forces of Chaos managed to make landfall upon Cadia itself and occupy large swathes of the planet despite ferocious Imperial resistance. The campaign was kicked off by the unexpected betrayal of the Volscani Cataphracts of the Astra Militarum, whose regiments successfully assassinated the Cadian High Command, including the Lord Castellan, the Cadian Planetary Governor. Led by the skilled strategist Ursarkar E. Creed, the Colonel of the 8th Cadian Regiment who was suddenly vaulted to the position of Lord Castellan, the Imperial forces were able to contain the initial Chaos assault and hunt down most of the occupying forces after the defeat of the initial Chaos armada in orbit.
Unfortunately, the Despoiler had barely begun to fight. He unleashed a massive second Chaos warfleet on the Cadian System and a ground assault that was led by one of his Chosen, Urkanthos, the Lord Purgator of the Black Legion. Urkanthos led a massive horde of Chaos Space Marines, Chaos Cultists and daemons against Kasr Kraf, the Cadian fortress-city that represented the primary centre of Imperial resistance. When Urkanthos was slain in the wake of the Living Saint Celestine's arrival and Kasr Kraf was saved, she bought the Imperials enough time to move their defence to the Elysion Fields, the largest grouping of Cadian Pylons on the planet. It had become clear in the course of events that Abaddon's true reason for constantly assaulting Cadia had always been the destruction of these pylons.
The Archmagos Dominus Belisarius Cawl, another recent arrival to the Fortress World, had been led to Cadia by the Harlequin Shadowseer Sylandri Veilwalker, and believed that he could decipher the true function of the pylons. With the aid of the Necron Lord Trazyn the Infinite, who had been present when the pylons were first constructed, Cawl proved capable of mastering the enigmatic xenos artefacts' internal systems deep in the catacombs beneath the pylon field. But this came just in time for Abaddon to launch his final ground assault against the Elysion Fields, as the Despoiler was determined to assuage his pride by personally ending the Imperial defence.
Once Cawl successfully activated the pylon network and cut off the access of the assaulting Chaos forces to the Warp -- even the Eye of Terror began to shrink as it was struck by the pylons' anti-psychic emissions -- Abaddon abandoned his desire to crush Cadia's defenders personally. Finding a modicum of grudging respect within himself for the Imperials' valour, the Despoiler decided instead to unleash his horrific fail-safe plan. He launched the remaining bulk of the Blackstone Fortress Will of Eternity, badly damaged by the assault of the Imperial Fists' star fortress Phalanx, into the surface of Cadia like an artificial meteor.
Cadia shuddered from that impact, as impossible forces jarred it loose of its age-old orbit. The survivors clinging to the ruined fortresses of the continent of Cadia Tertius barely had time to scream. Those beneath the vast impact site perished first, super-heated wind roaring in their ears before it seared flesh from bone, and reduced bone to scattered ash.
The Blackstone Fortress' remnant struck, gouging a crater hundreds of miles in breadth. Mountains crumbled to dust. Seas vanished into plumes of scalding steam. Continental plates rumbled and groaned as they shifted beneath titanic forces not seen since Cadia first cooled from the star-stuff of the galactic void.
The tremors spread, tidal waves and screaming particulate winds their heralds. Coastal bastions that had survived bombardment and siege drowned beneath the unnatural tide, ripped from their foundations and dragged beneath the squalling seas. The island of Ran Storn vanished entirely, its shell-ravaged landing fields drowned beneath the waves. A thousand miles inland on the continent of Cadia Secundus, the enduring spires of Kasr Vark at last fell, smashed apart by the waters of the Caducades Sea as the tidal shelves buckled.
Forests that had been old when Humanity first settled Cadia burned away in the briefest of moments. Crustal platelets shattered and split, the furious life-blood of the world boiling forth. Long-dormant volcanoes flared to life along the Rossvar Mountains, pyroclastic flows consuming all in their path. The great killing fields of Tyrok, site of Creed's ascension to the rank of Lord Castellan, split asunder and vanished into magma-lit gloom, swallowed by the world's torment.
At the Elysion Fields, half a world away from the impact site, they heard the roar of the winds, and saw the dark onrush of particulate clouds that blocked out the sun. The canny sought what cover they could amongst the pylons and ruined war machines. The slow-witted perished, torn apart by the vaporised bones of Cadia.
The winds grew, hurling tanks across the pylon fields, crushing those who had sought shelter beneath them. The ancient pylons gave up their grasp on the bedrock, toppling like petrified trees. The pylon field's beam of dark light cast outwards into the void flickered as the monoliths fell. The retreat of the Immaterium faltered, and then slowly reversed as the Eye of Terror began to expand once more.
The storm raged for solar minutes that seemed eternities, and then fell away into hurricane winds. They blew over a world forever altered. The continent of Cadia Tertius was gone, obliterated by fire and drowned beneath howling seas. The Krian Fault, bane of Cadia Tertius since the Age of Strife, had ruptured one last, fateful time, and the planetary crust split apart. Cadia Primus was half-drowned, its forested mountainsides now isolated islands scattered across a new ocean. Cadia Secundus lay wreathed in fire, its continental plates sinking as the pressure of their neighbours forced them steadily inwards. None of it mattered. Cadia was already dead.
But even then, there was worse to come. As the aftershocks of impact rippled through the dying rock, more pylons shattered against the dust-strewn tundra -- not just at the Elysion Fields, but at the lesser sites of Kasarn, Trosk and Vorg. As the pylons fell, the nodal web stuttered, and then withered entirely. The dark light beam, Belisarius Cawl's dagger struck into the heart of the Eye of Terror, flickered once more, and died. A new sound pealed through the howling winds -- the dark laughter of gods too long denied their prize. The crimson maelstrom of the Eye of Terror pulsed anew, and reached out to embrace sundered Cadia.
Save for the presence of the pylons, the Immaterium would have claimed Cadia long ago. The long-dead Necron artisans who had set the pylon fields in Cadia's living rock could not have foreseen the Eye of Terror's cataclysmic birth, could not have known the vital bulwark their works would become. But now, with the pylons' fall, the tendrils of the Warp laid their first loving caress upon Cadian realspace, and the daemons of the Dark Gods spilled forth.
These were not the flickering manifestations so lately loosed upon the world, their presence in realspace under constant challenge by the pylons' power. These were the servants of the Ruinous Powers, hale and whole, fed by the raw stuff of Chaos. They first appeared amidst drowned Cadia Tertius, where the Blackstone Fortress' demise had torn a rent in reality's veil through the sheer loss of life. But as the Eye of Terror slipped its ancient bounds, the rifts multiplied, dragging the beleaguered world into the bowels of the Immaterium.
The monstrous kinetic strike wiped out most of Cadia's remaining defenders, destroyed the network of Cadian Pylons and tectonically destabilised the world. As the Warp and its foul denizens claimed the remains of the Fortress World, Lord Castellan Ursarkar E. Creed arranged an evacuation of the planet that saved 3 million of its citizens before the planet finally ripped itself apart -- though not before Creed himself mysteriously disappeared.
The fall of Cadia represented a once-unimaginable triumph for the servants of the Dark Gods, and the Eye of Terror began to slowly expand without limit, opening Abaddon the Despoiler's coveted Crimson Path to Terra and creating the Great Rift that soon divided the Imperium in half.
Yet among the few survivors of Cadia was a handful of Imperial heroes who had successfully escaped the destruction of the Fortress World with the aid of the newborn Eldar faction known as the Ynnari. The combined forces fled through a Webway gate found on the ice moon of Klaisus in the Cadian System. Together, these Imperials -- the so-called Celestinian Crusade -- would forge an uneasy alliance with the enigmatic xenos that would offer a new hope for the servants of the Emperor in their fight against the waxing power of the Archenemy -- the resurrection of the Primarch Roboute Guilliman.
At the culmination of Abaddon's 13th Black Crusade, the Cicatrix Maledictum had all but consumed Cadia. With the great pylons toppled by Abaddon's conquering hordes and the colossal Warp Storm of the Eye of Terror no longer held at bay, the dread powers of Chaos ravaged the planet beyond recovery. And still the neighbouring worlds and star systems were defiant.
Had Cadia not been famous for holding so long against the odds, it is likely the other planets in the system would have capitulated or given up almost immediately. No normal world could stand in the face of the horrendous, sanity-devouring armies that descended upon the Cadian Gate in such terrifying measure. However, the wider systems of Cadia, Belis Corona, and Agripinaa stood fast.
Perhaps, just as a veteran can lead lesser men to deeds of great heroism, Cadia had inspired those worlds around it to defend every nation and city to the last bullet. Perhaps Cadia's surviving soldiery lent strength through their hunger for retribution. Perhaps those battered by the storm simply fought for survival. Whatever the reason, the defenders of the Cadian Gate resolved to uphold the virtues of its lost lynchpin world come what may.
In the confusion of outright war, the hordes of Chaos began to turn upon themselves. Though they were ascendant, their ultimate conquest had yet to be clinched. Rival warlords, both mortal and daemonic, clashed over the spoils of victories not yet won. The Imperial defenders were quick to capitalise on each strategic misstep,for many were veterans of the wars upon Cadia, and they knew how to goad a fractious enemy into overextending its reach. From dissolution came destruction. Solar day by solar day the Imperial armies clawed back a semblance of control. Soon the war zone was in contention once more, the dread stranglehold of Chaos loosened by the sheer determination of the Astra Militarum and the vengeful fury of the Space Marines. Each new dawn was greeted by a scattering of ships from the Great Exodus, those fortunate souls who had braved the Empyrean tempests and lived to tell of it. Again and again the fighting escalated, the fires of war that had burned Cadia to cinders roaring to life anew upon the other worlds of the Cadian System, as well as those of the Belis Corona and Agripinaa Systems.
Cadia was known to have at least three major landmasses, the continents of Cadia Primus, Cadia Secundus and Cadia Tertius. As noted, these continents possessed a wide variety of biomes and ecosystems, stretching from arctic tundra in the far north to boreal forests of the coniferous, pine-like axel-trees and temperate plains in the milder latitudes. The Cadian Pylons tended to be clustered in large fields of many monoliths, including such regions as the Elysion Fields, which possessed the largest concentration of the xenos constructs, as well as at the lesser sites of Kasarn, Trosk and Vorg.
The Cadian Pylons
In a galaxy replete with mysteries, the Cadian Pylons are amongst the most enduring. There are over five thousand such edifices scattered across the surface of Cadia, each one standing some five hundred yards above the surface, and reaching two hundred and fifty yards below. Reports differ, but it is understood that there could be anywhere between two and three thousand more concealed below ground as the result of tectonic movement down the ages.
Despite millennia of study, the Adeptus Mechanicus failed to discover the purpose of the pylons. Servitors sent within invariably ceased to function or suffered circuit overload; all attempts to breach the structures' gleaming surfaces met with failure. Any recovered data was fragmentary at best, and contradictory at worst. Even the identity of the pylons' creators was shrouded in mystery.
Some amongst the Cult Mechanicus believed the spires to be the work of the Necrons, or their mortal antecedents the Necrontyr, but then there were those on Mars equally convinced that the pylons were constructed by the Old Ones for the sole purpose of destroying the Necrons and their former C'tan overlords. The one thing all investigators agreed upon is that the pylons are responsible for the stable Warp-corridor known as the Cadian Gate. Adepts conjectured that they emitted a becalming signal, taming the roiling energies of the Immaterium.
This mystery was finally solved during the 13th Black Crusade by Archamgos Dominus Belisarius Cawl with the aid of the Necron Lord Trazyn the Infinite, who had been present when the pylons were first constructed eons ago, proving those Adepts who had long believed the pylons to be Necron creations correct. The pylon fields actually constituted a planet-wide nodal network that could be used to produce an unknown anti-psychic energy field capable of repulsing eruptions of the Warp into realspace. It was this network which had indeed kept open the Cadian Gate for millennia, and the sudden failure of which allowed the Eye of Terror to begin to expand across the galaxy, providing an anchor point for the eventual development of the Great Rift that cut the Imperium in half after the end of the 13th Black Crusade.
Society and Economy
Cadia was the home of the Imperial Guard's Cadian Shock Trooper Regiments, widely regarded as the best soldiers in the Imperium short of the superhuman Space Marines, as a result of their upbringing in Cadia's martial culture. Their leader was the indomitable Lord Castellan Ursarkar E. Creed, the saviour of Cadia and a hero of the 13th Black Crusade. Since Cadia is the capital world of the Cadian Sector and is often raided by various alien civilisations like the Eldar and Orks as well as the Forces of Chaos, the planet was heavily fortified. All Cadians were required to serve at least a four-year-term in the planetary military, and the amount of military presence on the world lead to the civilian population becoming focused on weapons production. 71.75% of the Cadian population was under arms, either in the highly-skilled and very well-equipped Cadian Planetary Defence Force that was known as the "Cadian Interior Guard" or in the numerous Imperial Guard regiments drawn from the planet's people. One out of every ten Cadians was recruited into the Interior Guard, regardless of ability or achievements, and as a result some of the most able human soldiers in the galaxy spent their entire Imperial military service on Cadia. The troops of the Interior Guard were amongst the most skilled fighting men in the Imperium, the equal of many other worlds' Imperial Guard regiments. Because of its closeness to the Eye of Terror and the constant risk of Chaos corruption this entails, Cadia also maintained the "Cadian Internal Guard" for defence against Chaos Cult activities. A less well-known part of the Cadian military establishment, the Internal Guard consisted of Inquisitors of the Ordo Malleus who had been permanently seconded to the Cadian military, and the Interior Guard made frequent use of Sanctioned Psykers to root out Heretics and mutants.
Chaos Space Marines from the Eye of Terror made often launched raids onto the surface of Cadia and had to be hunted down. The bulk of the Cadian army was made up of the Astra Militarum's Shock Trooper Regiments, with the remainder composed of the Whiteshields (conscript soldiers recruited at the age of 14 standard years and trained to take a place in the Shock Trooper regiments) and the elite Kasrkin soldiers of the Ordo Tempestus. Cadian regiments are consistently on average the most well-disciplined and most effective in the entire Astra Militarum.
Because of its heavy concentration on military matters, Cadia's global economy is dominated by the manufacture of various weapons systems and exports vast numbers of weapons to its neighbouring Imperial planets, while importing very little other than food. Many other worlds use Cadian equipment to arm their own Imperial Guard regiments, which explains how the Cadian Patterns of personal armour and infantry weapons have become the standard for the entire Astra Militarum.
Cadia had a special and honoured place in the history of Mankind. Cadia stood upon the edge of the Eye of Terror within a narrow corridor of stable space called the Cadian Gate. This formed the one and only predictable passage between the Chaos-infested Daemon Worlds of the Eye of Terror and Terra. It seemed that although many Chaos fleets had ventured out of the Eye, very few Imperial fleets ventured in. No battle fleet of any size could rely upon other stable passages from the Eye of Terror and they were required to pass through the Cadian Gate. Cadia was therefore one of the most strategically important planets of the galaxy. On several occasions the Forces of Chaos moved against Cadia and raging battles were fought in the depths of space. Such huge battles were rare, but the constant intrusion of Chaos raiding craft into Cadian space was commonplace throughout the period of the Long War.
Before the later Imperial re-colonisation of the world in the 32nd Millennium, Cadia was the home of a lost fragment of humanity that worshiped the four Chaos Gods, probably since the onset of the Age of Strife. This society was encountered by the then-still-Loyalist Word Bearers Legion 40 Terran years before the outbreak of the Horus Heresy, and the prevalence of violet eyes amongst the populace was seen as a mark of mutation caused by the proximity of the Eye of Terror, which also appears violet in the visible light spectrum. This civilisation was eventually wiped out by the Word Bearers Space Marine Legion in the late 30th Millennium at the conclusion of the Pilgrimage of Lorgar. Cadia was later resettled by Imperial humans of all creeds and genetic stock. The Cadian people of the 41st Millennium were naturally tall and solidly built. The fact that this new line of Cadians of untainted Imperial stock also sported violet eyes lends credence to the theory that the proximity of the Eye of Terror caused this mutation.
Cadian society in the 41st Millennium is more martial than civilian, mostly due to the disproportionate ratio of soldiers to citizens in its population. The birth rate and the military recruitment rate are synonymous. Most Cadian children learn to field-strip a Lasgun by the age of ten standard years, and many young Cadians served in the Astra Militarum as Whiteshields. Cadian society was so martial that camouflage patterns made their way into the everyday fashion of even the wealthy and successful. It was always very easy to determine who was an outsider or local on Cadia simply by what they wore.
Being a constantly embattled world, Cadia suffered numerous casualties in the defence of the Cadian Gate and the Imperium. Cemetery space on the planet was at a premium so the local priests of the Imperial Cult routinely checked the grave markers of the honoured dead for legibility. When a section of a Cadian cemetery's grave markers were deemed illegible, those graves were exhumed and the bones were added to a communal pit. The Cadian belief was that once the names on a grave marker were illegible, the honours of those dead were forgotten.
Long ago Cadian cities changed from a plan of broad avenues to one where the streets of its cities were arranged in zig-zag patterns meant to make any intruding enemies fight for every block. At the heart of each Cadian city was a fortress called a Kasr in the local dialect of Low Gothic. The largest Kasr as of 241.M41 was Kasr Derth. Cadia's earliest Kasrs had been built in the High Terran Style, with the wide streets laid out on a grid system. Early in the 32nd Millennium, soon after the planet's resettlement, during the first of the Black Crusades, most of the Cadian Kasrs were destroyed by the Chaos invasion. The broad, ordered avenues of the Kasrs had proven impossible to hold or defend. Since then, the Kasrs were rebuilt in elaborate geometric patterns, the streets juking back and forth like the teeth of a key. From the air, Kasr Derth looked like an intricate angular puzzle. Given the Cadians' mettle and their skills at urban warfare, a Kasr could be held street by street, metre by metre, for solar months if not standard years.
Many notable Imperial Navy battlefleets protected the surrounding systems of the Cadian Gate by constantly patrolling the space lanes around the Eye of Terror, always vigilant for Chaos raiders or another approaching Black Crusade.
Notable Cadian Astra Militarum Regiments
Many notable Astra Militarum regiments have been drawn from Cadia, including:
- 7th Cadian Regiment, "The Lucky Sevens"
- 8th Cadian Regiment, "The Lord Castellan's Own" - The 8th Cadian was led personally by Lord Castellan Ursarkar E. Creed during the 13th Black Crusade.
- 39th Cadian Regiment,"Xenobane"
- 69th Cadian Regiment, "The Fighting 69th"
- 81st Cadian Armoured Regiment, "Rolling Thunder" - The 81st Cadian were also known as the "Gunheads". They fought on the Ork World of Golgatha where they were at first lead by Colonel Kochatkis Vinneman, and later by Lieutenant Gossefried van Droi.
- 88th Cadian Regiment - The 88th Cadian Regiment fought for the retrieval of Commissar Yarrick's Baneblade super-heavy tank The Fortress of Arrogance on the Ork World of Golgatha. The regiment was lead by Colonel Edwyn Marrenburg.
- 89th Cadian Armoured Regiment, "Steel Lords"
- 98th Cadian Regiment, "The Fighting 98th" - The 98th Cadian Regiment fought for the retrieval of Commissar Yarrick's Baneblade super-heavy tank The Fortress of Arrogance on the Ork World of Golgotha. The regiment was lead by Colonel Tidor Stromm.
- 110th Cadian Regiment, "Shadow Corps"
- 122nd Cadian Regiment - Distinguished themselves in the Vogen Campaign
- 203rd Cadian Regiment - The 203rd Cadian Regiment fought beside the 2nd Company of the Ultramarines Chapter that was commanded by Captain Titus during the Imperium's liberation of the Forge World of Graia during the events of Space Marine. The regiment's remaining forces were commanded by 2nd Lieutenant Mira.
- 412th Cadian Regiment - Featured in the PC game Dawn of War: Winter Assault where they carried out the Imperial assault against the Chaos Space Marine and Ork forces of the ice world of Lorn V
- 417th Cadian Regiment, "Hellbringers"
- 516th Cadian Regiment, "The Wildcats"
Last Defence of Cadia (13th Black Crusade)
Imperial Order of Battle
The final battles of Cadia had prevented the disaster of the 13th Black Crusade from being total. Though Cadia itself was lost, the defence of Kasr Kraf held up Abaddon's final assault, and the mayhem that followed allowed a great number of troops and military assets to reach the Imperial evacuation zone and depart.
Defence of Kasr Trunch
- Cadian Shock Troops - 127 Regiments
- Cadian Kasrkin - 65 Regiments
- Cadian Youth Corp - 12 Regiments
- Tithed Astra Militarum - 18 Regiments
- Skitarii - 5 Legions
- Siege Auxilia Corps - 528 Batteries
- Legio Metalica - A Demi-Legion
- Adepta Sororitas, Order of the Bloody Rose - 2 Preceptories
- Adeptus Astartes
Kasr Trunch Counterattack
- Black Consuls - 6 Companies
- Watchguards - 6 Companies
- Varied Astartes Chapters - 12 Companies
- Officio Assassinorum - Classified
The Long Retreat
- Cadian Shock Troops - 41 Regiments
- Cadian Kasrkin - 16 Regiments
- Zenonian Free Companies - 9 Companies
- Tithed Astra Militarum - 12 Regiments
- Dhonovar Heavy Armour - 5 Companies
- Legio Cybernetica - 3 Cohorts
- Adepta Sororitas, Order of the Ebon Chalice - 3 Preceptories
- Hallicon Armoured - 5 Regiments
- Ordo Reductor - A Demi-Legion
- Legio Ignatum - Full Legion
- Adeptus Astartes
Note: All the Adeptus Astartes assets were stripped from Mos Khazner's defence in an attempt to retake the orbital batteries. Their success allowed the Long Retreat.
The Lord Castellan's Last Stand
- Cadian Shock Troops - 99 Regiments
- Cadian Kasrkin - 6 Regiments
- Brazen Claws - 3 Companies
- Black Consuls - 2 Companies
- Centurio Ordinatus - 4 Ordinatus
- Legio Gryphonicus - A Demi-Legion
- Freeblades - Unknown
- Skitarii - 3 Legions
- Fort Drokz Penal Legions - 4 Legions
- House Krast - 2 Knight Households
- Legion of the Damned - Unknown
- Relictors - 2 Companies
- Harlequin Masque of the Hidden Path - 9 Troupes
- Varied Astartes Chapters - 5 Companies
Forces of Chaos Order of Battle
Abaddon the Despoiler led the final assault force against Cadia in person. With him came the legions of the hellish Eye of Terror, the manifold hosts of the Dark Gods amassed under a single banner. The cause that united them was not just the destruction of the Imperium, but the demise of the material realm itself.
- Black Legion - Full Traitor Legion
- Iron Warriors - Full Traitor Legion
- World Eaters - 5 Warbands
- Emperor's Children - Hedonistic Hosts
- Night Lords - 3 Warbands
- Death Guard - 3 Plague Companies
- Alpha Legion - Unknown
- Word Bearers - 5 Companies
- Legio Mortis - A Demi-Legion
- Khan'zhar the Red - Exalted Greater Daemon of Khorne
- Bloodguard - 8 Greater Daemons of Khorne
- Redhost - 8 Daemonic Legions
- Fellblades - 8 Daemonic Legions
- Kaghrexx's Destroyers - 8 Daemonic Legions
- Khârn the Betrayer - Legendary Chaos Lord
- Gorehands - 5 Companies
- Blood Engines (Traitor Astra Militarum) - Armour Battalion
- Skullcorps (Traitor Astra Militarum) - 18 Regiments
- Bloodemption - Chaos Cult
- Slogoth Poxbelly - Exalted Greater Daemon of Nurgle
- Drub'sla Plaguehost - 7 Daemonic Legions
- Three-Eyed Tolltakers - 7 Daemonic Legions
- Blightwalkers - 7 Daemonic Legions
- Nurgling Tide - Uncountable
- The Tainted - 7 Companies
- The Horned - Pestigor Legion
- The Risen - Plague Zombies
- Ogryn Brutepox - 3 Companies
- The Stigmatus Convent - Entire Chaos Cult
- The Viscous - Entire Chaos Cult
The Host Iridescent
- M'katchnar - Exalted Greater Daemon of Tzeentch
- Triumvirate of Arcanzarr - Daemon Coven
- Scintillating Host - 9 Daemonic Legions
- Legions of Shimmerlak - 9 Daemonic Legions
- Unkbolt Conflock - 9 Tzaangor Warflocks
- The Scourged - 4 Companies
- Eagles Iridescent - 3 Companies
- Kabal of Umbra - Entire Chaos Cult
The Decadent Horde
- Sidroh the Sinuous - Exalted Greater Daemon of Slaanesh
- The Writhing Host - 6 Daemonic Legions
- The Undulators - 6 Daemonic Legions
- Violators - 5 Warbands
- Children of Torment - 3 Warbands
- Pain Armoured Brigade - 2 Sonic Companies
- The Hedonastic - Entire Chaos Cult
- Tentacled Behemoth - Warp Monster
As befits Abaddon's cruelty and meticulous planning, thirteen massive transports of combat-drugged mutants, wretches, Plague Zombies and Chaos Spawn were crash-landed into the ruined city of Kasr Kharkovan, ensuring that many of the final assaults were performed by the least storied among his armies.
- 13th Black Crusade
- 13th Black Crusade (Original)
- Roboute Guilliman
- Ultramar Campaign
- Terran Crusade
- Great Rift
- Indomitus Crusade
- Cadian Gate
- Codex: Chaos Space Marines (6th Edition), pp. 20, 25, 57
- Codex: Chaos Space Marines (5th Edition), pg. 46
- Codex: Chaos Space Marines (3rd Edition, Revised Codex), pp. 8, 81
- Codex: Eye of Terror (3rd Edition), pp. 5, 11, 24, 37
- Codex: Imperial Guard (5th Edition), pp. 14, 57
- Codex: Imperial Guard (2nd Edition), pg. 11
- The Gathering Storm - Part One - Fall of Cadia (7th Edition), pp. 10, 68-88
- The 13th Black Crusade (Background Book) by Andy Hoare
- Warhammer 40,000: Rulebook (8th Edition), pg. 161
- White Dwarf 182 (UK), "Cadian Shock Troops: Imperial Guard," by Rick Priestley
- The First Heretic (Novel) by Aaron Dembski-Bowden
- The Eisenhorn Trilogy (Novel Series) by Dan Abnett
- Eye of Terror Worldwide Campaign - Newletters