Battlefleet Cadia is a colossal fleet of Imperial Navy vessels charged with the protection of the vital and strategically important Cadian Sector within the Segmentum Obscurus. The Fortress World of Cadia stands at the center of the sector and its people serve as the unflinching sentinels of the Cadian Gate. Battlefleet Cadia aided Battlefleet Gothic during the 12th Black Crusade, known also as the Gothic War, which lasted from 139.M41 until 160.M41. More recently, Battlefleet Cadia suffered severe losses during the recent 13th Black Crusade which occurred in 999.M41. Portions of Cadia are currently occupied by the Forces of Chaos, following the indecisive outcome of this epic conflict. Now that the servants of the Dark Gods have finally established a foothold within Imperial space, Cadia is currently circled by several Imperial Navy battlefleets, including its own, and the maintenance of this space superiority is all that is keeping the Forces of Chaos from staging their first breakout into Imperial space en masse since the end of the Horus Heresy.
The Segmentum Obscurus, also known as the Segmentum Obscura, is the region of Imperial space to the galactic north of Terra. This Segmentum of the Imperium of Man is the home of the vast Warp Storm and Warp Rift called the Eye of Terror, the primary home for the Forces of Chaos in the Milky Way Galaxy. The Imperial Navy's Segmentum fleet headquarters is located on Cypra Mundi, which also serves as the central headquarters of the Imperial military's Segmentum Command. The Segmentum Obscurus is the area of the Imperium most often under deadly threat by attacks from the Eye of Terror and is also the site for all of Abaddon the Despoiler's Black Crusades. As such, it currently is home to the majority of the Imperium's armed forces, which were most recently mobilised to a state of readiness not seen since the Horus Heresy as a result of the 13th Black Crusade in 999.M41.
The constant turmoil surrounding the Cadian Gate requires Battlefleet Cadia to be far more active than many other battlefleets. The whole sector exists in an almost perpetual state of readiness, and as such the demands on manpower and resources are huge. Vast numbers of new, inexperienced ratings frequently have to be drawn up to replace those lost in the constant fighting (many of them drawn from worlds within the Cadian System itself such as Vigilatum and Macharia). However, those that survive the harsh first years of military service around the Cadian Gate rapidly mature to become some of the most capable leaders in the Imperium. As with all highly militarised zones, it is important for the Imperial Navy to maintain substantial reserves of vessels around the Eye of Terror, ready to deploy as reinforcements should the need arise. Whilst it is possible to keep the vessels themselves ready in this manner, Battlefleet Obscura simply does not possess the manpower to keep reserve crews stationed aboard these vessels as well. Instead, whole orbital shipyards are filled with rows of silent, inactive vessels, often representing classes of warship now outdated or scarce.
In times of great need, these ships will be brought into service and crewed with ratings from destroyed or crippled vessels or even with hastily mustered new recruits, meaning the crew is unlikely to have any familiarity with their new vessel. A posting to such a reserve fleet is thus considered an unnerving duty, forcing a rating to enter deep into an unfamiliar vessel which may have lain dormant for centuries. Much superstition surrounds such fleets and perhaps because of this, unusual behaviour of both crew and vessel is rather commonplace. Reserve fleets are used only reluctantly by the Imperial Navy, and only in the most desperate of circumstances, but an invasion the size of Abaddon's 13th Black Crusade without doubt qualifies as exactly that -- the most dire of circumstances, the most desperate of times.
In a reserve fleet, all vessels are prone to certain unexpected events, such as mass panic or even mutiny amongst the crew, inexplicable noises, sensor readings and sightings or disconcerting setbacks and failure of machinery. Against Chaos fleets, where the followers of the Dark Gods are able to exert their influence to further unsettle their already nervous opponents, unforeseen events can be even more devastating.
13th Black Crusade
The beginning of Abaddon's 13th Black Crusade was marked by an escalation in the number of raids on isolated, seemingly insignificant worlds in the sectors outlying the Eye of Terror. Such raids, whilst certainly not unusual, had previously always been the work of small groups of pirates, acting without common motive, and invariably dogged shipping lanes and the like, rather than directly attacking Imperial settlements. This new wave of attacks seemed too highly coordinated, based on far too detailed a plan to simply be the work of the wolf packs. Something terrible was clearly emerging.
Rashes of Warp flares erupted all around the Eye of Terror, making travel impossible, disrupting communication and breaking supply lines. Around these Warp flares, small Chaos Warfleets emerged to prey upon those Imperial vessels stranded in small numbers by the inhospitable conditions, brutally massacring them all. Most horrifically, alongside these emergent Chaos fleets, there came reports of weird, ethereal daemon ships, seemingly creatures of the Warp carried into the material realm on the tides of Chaos. Battlefleet Cadia and other Imperial fleets engaged these vessels where they could, though many reported them intangible and elusive, translating to and from the Warp at will, making their ambushes and raids all the more deadly.
Patrol groups from all local battlefleets dispersed across the Agripinaa Sector, the target of many of the fiercest and most brutal raids, hunting down and engaging the raiders where they could. The small raiding groups which Imperial command had anticipated invariably turned out to be drastically larger forces, and many of the Imperial patrols were lost before even being able to give accurate reports of the opposition they faced. It quickly became apparent that a system of patrol and interception would do little more than plug the holes, not cut off the leak.
Under such an atmosphere of uncertainty, the decision was made to withdraw fleet resources to dock, where larger, more effective battlegroups could be mustered and a common plan for defence determined. The captains of the returning vessels were grilled for what information they could provide on the growing threat, though so short and bloody had been their defeat that little of use could be gleaned. Confusing reports of Eldar vessels completely ignoring, or even aiding Imperial fleets, baffled many of those present, but the wisest amongst them realised instantly that such unexpected unity could only stem from a common enemy. A foe to trouble even the Eldar was about to descend upon the galaxy, it seemed.
It would not be long before confirmation emerged. Even as fleet commanders gathered in the Agrapinaa Sector to ponder their next move, news reached them of the Volscani Cataphracts' horrifying betrayal on Cadia. Chaos, it would appear, was not merely on their doorstep, but already deep within their house. The massacre on Cadia, however, meant that the Imperial fleets' numbers were bolstered dramatically in the following days, as reinforcements arrived from neighbouring sectors, including an almost unprecedented number of Chapters of the Adeptus Astartes also responding to the call for aid in the aftermath of the Chaotic massacre of the Cadian leadership at the Fortress World's Kasr Tyrok. The Gothic-class Cruiser Abridal's Glory even filed a report of a mobile Fortress-Monastery entering the region, suggesting that even to the Space Marines, the coming events were of the greatest importance.
Curse of Unbelief
Understandably, most of the arriving Chapters feared further revolts and uprisings across the sectors bordering the Eye of Terror, and almost all elected to begin ground offensives against those star systems where the strife and disorder had already become widespread. The Space Marines were similarly tasked with fighting through many of the raging Warp Storms and mounting assaults on the scattered and isolated worlds already fallen to the Curse of Unbelief. Here, the Space Marines would be far less hindered by the lack of numbers and adverse conditions than the Imperial Navy. Against a host of worlds the Adeptus Astartes fleets unleashed massive planetary assaults to corral and contain the spreading arcane contagion, using planetary bombardments (and in the worst cases, Exterminatus) to control areas already deemed unclean.
The best this strategy could hope to achieve, however, was to stabilise conditions on many of the smaller worlds across the affected sectors, where Imperial rule had been placed under the most strain. A far stronger defence would be required if Cadia and its neighbours were to be truly ready for what few now doubted would be a major Chaos invasion. To this end, the vast collection of warships assembled at the main sector docks around the Eye of Terror were formalised into battlefleets and dispatched to defend vital supply lines, inhabited worlds, and known routes out of the Eye of Terror. Foremost amongst these would be Battlefleets Cadia, Agripinaa and Scarus, who were detailed to act as the main crux of the Imperial fleet effort.
As these defensive preparations were made, unknown raiders hit the Tabor and Ulthor Systems, but this time vessels of the Imperial Navy were in position to counterattack. Three squadrons of Cobra-class Destroyers in conjunction with the Lunar-class Cruiser Goliath pursued the attackers into the Faberius Straits and in a fearsome battle crippled the Styx-class Heavy Cruiser Darkblood. The engagement cost the Navy most of the Cobras and the Goliath was severely damaged, but at last the attackers had been identified. The Darkblood was codified as being attached to the Night Lords Traitor Legion warleader, Tarraq Darkblood, one of the most vicious killers in a Traitor Legion replete with sadistic butchers. Before Imperial reinforcements could arrive, a huge force of Chaos warships were picked up on long-range augers, and the surviving Imperial vessels were forced to withdraw and limp to the safety of the nearby port of Aurent.
Similar opposition was met by many of the Imperial battlegroups. The Imperium was able, largely, to stave off these small Chaos incursions, but often at a great cost in resources, invariably forcing back the Imperial fleet and leaving it poorly equipped to repel any subsequent attacks. Reluctantly, the Imperial vessels withdrew, realising that some massive attack must be imminent and that their best hope lay in a single, combined defensive effort. This change in tack meant that the Imperium's highest priority very rapidly became predicting and preempting the location of any initial attack. The answer was to come in unimaginably bloody fashion.
The Storm Breaks
"Cadia, Agripinaa, Belis Corona – these are the worlds which will stand as the firmly barred gateways set amidst the unbreachable walls which we, the Imperial Navy, must now form. Titan, Mars and Ancient Terra – these are the glittering palaces within to which we must allow none to pass. So shall it be that we prove truly the bastion of all mankind."
A patrol group, delivering Cadian Kasrkin to the planet of Urthwart, were to make the discovery. They came upon Urthwart to find it already lost, enslaved utterly by Chaos. Nothing there could be saved, and the Kasrkin made ready to withdraw, perhaps suspecting they had arrived too late. In truth, the fact that they had arrived at all was the enemy's ultimate success. As the Cadians made ready to withdraw, the space around Urthwart was eclipsed by a Chaos fleet emerging from the Eye of Terror. At the centre of this armada of the Dark Gods, horrifying and incomprehensible, came the vast and terrible weapon known as the Planet Killer. In a matter of hours, Urthwart became a victim of the aptly-named Planet Killer -- the world and all it had ever contained committed instantly to history by this greatest of Abaddon's machineries. Like a herald of damnation, the arrival of the Planet Killer instantly announced to all that a new Black Crusade had well and truly begun.
As if answering some unspoken signal, the destruction of Urthwart coincided precisely with the emergence of Typhus' Plaguefleet, the fiend himself in command at the helm of his flagship, Terminus Est. The fleet was immense, accompanied most alarmingly by two Blackstone Fortresses (relics of Abaddon's previous incursions into the Gothic Sector) though now hideously altered so as to appear artefacts of Chaos rather than the ancient bastions they once were.
If a stand was to be made, it was now. The Imperial fleet amassed at Ormantep, within the boundaries of a vast asteroid belt known as the Ilithrium Belt. It was here that the forces of the Imperium and those of the Dark Gods at last came face to face. The disruptive effect of the asteroid belt forced the fleets into brutally close range combat. Hordes of Chaos Attack Craft, and torpedoes unleashed at close range where their accuracy was highest, decimated the Imperial fleet. Even the fleet flagship, Honour and Duty, under the command of Admiral Pulaski, fell prey to the hungry guns of Chaos and exploded as its internal damage got the better of the ancient vessel. While strength of numbers and sheer firepower may have been advantages that lay squarely in the hands of Chaos, unbreakable faith and courage remained as ever the epitome of the Imperial Navy. If victory could not be gained at Ilithrium, defeat would at least be stalled.
Captain Agenager, taking command of the fleet after Pulaski's demise, ordered the fleet into a cross formation, arranging their broadsides against the Chaos fleet where vessels could defend one another with massed firepower and turrets, fending off enemy Attack Craft and creating a vicious zone of crossfire to their port and starboard. The immobility of the formation left Agenager with little hope of escape, but would at least stall the Chaos advance. With his decision made, Agenager and his fleet steeled themselves for the fight, praying only that their sacrifice would not be in vain.
In the event, the sacrifice was not to be asked of them. As the Chaos fleet found itself stubbed by the unbreakable Imperial cross formation arrayed against them, its flanks first buckled then collapsed utterly as the mighty Battlefleet Agripinaa arrived to unleash its fury upon the Traitors. It was immediately apparent to Admiral Quarren, arriving at the head of the Battlefleet, that a final victory could not be achieved. Instead, his reinforcements could provide only respite and the chance of escape to their comrades -- a chance which all the assembled Imperial Navy vessels gladly took, departing at once for the relative safety of port at Demios Binary.
So it was that as Abaddon's 13th Black Crusade swept throughout the sectors bordering the Eye of Terror, the immense warfleet which he had amassed proving unstoppable. In comparison to Abaddon's Grand Fleet and the Plaguefleet of Typhus, the Imperium's defences were thinly spread, even around the Cadian Gate where the so-called Bastion Fleets stand as the largest permanent Imperial Navy element outside of the Solar System itself. Thus, in the early stages of the war, Abaddon's fleet held orbital supremacy across most of the sectors within the warzone, allowing him to bombard worlds, enslave their populace and deploy Chaos forces to the surface at will. All the while, however, the ponderous machine of the Imperial Navy readied itself slowly but surely against him.
The Imperial Navy is, ultimately, an inevitability. Stretched out across the thousands of light years of Imperial space, dispersed across a hundred warzones, patrol routes and shipping lanes, it is far from the most reactive force in the Emperor's service. Nonetheless, the Imperial Navy is a giant, an unstoppable behemoth which sooner or later will, inevitably, arrive to unleash its vengeance, no matter how powerful the foe. The Imperial Navy had been forced to divide its assets across hundreds of worlds at the outset of the war. However, as the conflict drew on it was gifted a valuable opportunity to combine its numbers and concentrate its forces once Abaddon's plans became clear and the Chaos fleets had delivered hordes of ground troops to important worlds such as Cadia, Agripinaa and Thracian Primaris.
Where Imperial defences had been overstretched at the outset of the war, they soon stood reinforced by dozens of neighbouring battlefleets. Tiny patrols, at first hopelessly outnumbered and overwhelmed by Abaddon's invasion, mustered together into battlefleets numbering hundreds of vessels. Space Marine Chapters committed their own fleets to the war in space and soon the Imperial Navy stood as an unbreakable circle of iron around Abaddon's forces. From this strong regrouping, Admiral Quarren was more than ready to launch his counter-attacks against Abaddon's chosen targets.
A thousand small battles were already lost for the Imperium, worlds engulfed by cults and treacherous defenders, worlds decimated by the Plague of Unbelief and other forgotten battlefields were already far past the point at which they might be saved. Indeed, fighting the war across a front scattered like a thousand broken shards had undoubtedly stymied the Imperium in the early days of the invasion, forced to spread its already hard-pressed assets, uncertain of where the hardest blow might land. To win the greater war now, the Admiral Quarren realised that a handful of crucial fronts must be all to which the Imperium committed. So it is that the course of a war, the story of victory and defeat , cannot be described in terms of all its constituent parts, but instead must be thought of in terms of those particular prizes for which both sides tussle most fiercely -- worlds like Agripinaa, Nemesis, Subiaco Diablo and most of all, Cadia and its ancient Pylons.
The Imperium Resurgent
As Quarren’s reunified, reinforced and reinvigorated fleet moved towards Cadia, the Chaos fleet, including one of the Blackstone Fortresses, ancient engines of destruction built aeons ago by unknown xenos, gathered above the planet. In a manner none could have predicted, the Chaos fleet was unexpectedly delayed by lightning-fast attacks on the Blackstone by squadrons of Eldar Cruisers. Lord Admiral Quarren was quick to take advantage of the delay and his counter-strike (composed of vessels arriving from out of system) flowed from Cadia to Xersia and finally Demios Binary. In his first action, Quarren chose to strike directly at the vessels in orbit around Cadia itself. The vast majority of Abaddon's forces had already been committed to the planet, so Quarren could do little to aid the struggle there, but his fleet did now have a massive opportunity to retake control of the space around Cadia and prevent Chaos reinforcements.
Quarren attacked the Chaos fleet side-on, trapping the Traitor vessels between his own fleet and the planet Cadia where their superior speed would provide them little benefit. Even with the enemy trapped, the Chaos fleet still presented a fearsome amount of firepower. By dint of this cunning stunt, Quarren succeeded, first in dividing the main fleet, and then in pursuing the defeated elements to final extinction. Only those squadrons that stayed close to the Blackstone Fortress remained a threat, but the Chaos fleet was now concerned with survival. Most significantly, the Imperial flagship Galathamor crippled the Merciless Death, driving it to the Warp from whence it took no further part in the war.
As an act of vengeance, Abaddon dispatched the Planet Killer to Macharia within the Cadia System. A desperate boarding action by Space Marine Honour Guard companies failed to prevent the Planet Killer firing, but damaged its shields. As a consequence, debris from the shattered world that had once been Macharia struck the Planet Killer, which was last seen tumbling away into Wilderness Space critically damaged. When worlds in the Cadia System fell prey to the opportunistic Dark Eldar, the Relictors Space Marines stood ready and swiftly repelled the raiders, driving them back to their fleet. The Dark Eldar could not have expected Admiral Quarren would have set his fleet in motion so swiftly after fighting the Chaos fleet. His vanguard smashed into the Dark Eldar fleet and inflicted terrible damage and drove them out of the war in the Cadian Sector.
At the Cadian Sector world of Kasr Patrox, the Traitor Legions of the Chaos Space Marines scored an immeasurable victory, though would themselves be slain by a most unexpected foe. High above them oblivion beckoned in the monstrous form of a corrupted Blackstone Fortress. The Blackstone Fortresses' weaponry beat down on Kasr Partox, remorselessly slaughtering the warriors of both sides. Faced with the certain destruction of Cadia's last defenders, Admiral Quarren had no choice but to muster his battered fleet for yet another battle. One by one the screening Chaos vessels were peeled away from the Blackstone until eventually it was forced to cease its attack and concentrate upon its own defence. With the end of the Blackstone's attack an uneasy lull settled on Cadia during which Lord Castellan Ursarkar Creed evacuated Kasr Partox while he still could.
Notable Vessels of Battlefleet Cadia
- Galathamor (Emperor-class Battleship)
- Vigilanti Eternas (Vengeance-class Grand Cruiser)
- Goliath (Lunar-class Cruiser)
- 12 Battleships
- 12 Cruiser Squadrons
- 21 Escort Squadrons
- Battlefleet Gothic Armada, pp. 14, 29
- Codex: Eye of Terror (3rd Edition), pg. 8
- The Thirteenth Black Crusade (Sourcebook) by Andy Hoare
- Eye of Terror Worldwide Campaign - Newletters