The Cyclops Cluster is a heavily industrialised Imperial sub-sector whose origins date back to the sixth decade of the Great Crusade. It is located at the galactic northeastern border of the Segmentum Obscurus with the Ultima Segmentum and is counted amongst the wider regions of the Coronid Deeps of the famed Gothic Sector. Designated -- according to legend -- by the hand of the Emperor Himself for further colonisation and exploration, the Cyclops Cluster quickly rose to prominence, being only overshadowed by the might of the neighbouring Manachean Commonwealth. With those planets of the Manachean Commonwealth, the Cyclops Cluster formed the heartlands of the Coronid Deeps, far more advanced and valuable then those planets of importance within the Grail Abyss or the Coronid Reach.  

Through its great amount of mineral wealth, the world of Dominica Minor quickly rose to become the regional power to which the other planets of the sub-sector looked for guidance. Given its economic output, it should then have come as no surprise that the Cyclops Cluster would become the first Imperial sub-sector to come under attack by Traitor forces in the opening year of the galactic civil war known as the Horus Heresy


In stark contrast with the neighbouring worlds of the Manachean Commonwealth -- whose history stretches back into the Dark Age of Technology -- but with notable exceptions such as the worlds of Mezoa, M'Pandex and Dark Haven; the Cyclops Cluster has only recently been colonised by humanity after the Great Crusade reached this region of space in the late 800s of the 30th Millennium. This is perhaps best explained by the Cyclops Cluster's astrography, which features only a few readily inhabitable worlds for such a vast stretch of space. The Cluster, however, proved rich in mineral wealth and other much-needed ressources that made it a valuable prize for the ever-growing Imperium. Apart from the Mechanicum Forge World of Mezoa, the Cyclops Cluster suffered little from the depredations of the xenos empire known as the Mitu Conglomerate which was successfully annihilated by the Emperor's armies. In the aftermath of this campaign the Cyclops Cluster received the visit of several Expeditionary Fleets, amongst these both the 611th and 7th Expeditionary Fleets, the latter proving the more active. Under the command of Commander Suleiman Grimm of the I Legion, the Dark Angels, the 7th Expeditionary Fleet would rally such worlds as Dark Haven and Mezoa and peacefully obtain their Imperial Compliance before sailing northwards to the Grail Abyss

Ancient Departmento Cartigraphicae map showing the regions of the Coronid Deeps; the Cyclops Cluster lies in the southwestern corner

As the Cyclops Cluster's wealth gradually became more widely known, the new sub-sector became one of the priority targets for Imperial colonisation efforts, counting as it did two fully-fledged Forge Worlds amongst its ranks and dozens of promising star systems ready to be exploited. The colonists needed to be shipped in from various regions of the Imperium's more settled heartlands, requiring the transport of entire planetary populations, much of them translating through the dormitory world of Moab before being shipped to their final destination. Soon the Cyclops Cluster counted sixteen primary-grade industrialised worlds and no less than ninety-three distinct resource extraction zones.

By the end of the Great Crusade, the Cluster had become a powerhouse of activity, its economic output only surpassed by that of the Manachean Commonwealth. Harsh production quotas had been imposed on most worlds of the Cyclops Cluster, whose populations had to toil hard to meet them. This naturally bred dissatisfaction, which was often brutally repressed by the imposition of martial or Mechanicum law. Local power was nearly nonexistant, the world of Dominicia Minor's rise to prominence in the region manifesting only in the decades immediately preceding the outbreak of the Horus Heresy.

Thus, for much of its existence, the Cyclops Cluster was governed by Imperial authorities residing in the Segmentum Solar, which did not fail to breed embittered and resentful populations that came to view the Imperium as uncaring, distant and harsh masters that gorged themselves on their misery and labour. As a result petty worker revolts and strikes were commonplace decades before the Warmaster Horus' treachery, the brutal repressions by Imperial power only perpetuating the vicious circle Horus would eventually prey upon at the dawn of the Heresy.

The Horus Heresy

As one of the most productive regions of the wider Coronid Deeps, it was only a question of time until the Cyclops Cluster would come under attack by traitorous forces, the Cluster harbouring not only two fully-fledged Forge Worlds but also countless mining and other resource exploitation facilities as well as a few Agri-worlds that would form an ideal power base for Horus' shadow empire.

Other factors also spoke for the rapid invasion of the Cyclops Cluster by the Traitors; first because the Warp-routes to the Cluster were well-known and still free of the ever-increasing turbulence that began to plague Warp-traffic at this time and second because the Cyclops Cluster formed a perfect stepping stone to Horus' ultimate goal in this region, the conquest of the Manachean Commonwealth and the Armada Imperialis Port Majoris at Port Maw. What would become known as the "Scourging of the Cyclops Cluster" would then stand as the first chapter of the Manachean War.

Enemies at the Gates

"Bow before Him who is the Warmaster, abase yourselves befor His truth. Serve those who serve Him, harken only to their words.The Imperium is His. Mankind is His. You are His. Submit to the Warmaster, or die by His hand. There is no other choice, and you will be given the chance to kneel but once. Horus is Lord. Horus is Death."

—Message left to Gethsamaine's Planetary Governor

As a frontier realm of the Imperium, the worlds of the Cyclops Cluster were used to a prolonged and heightened state of alert, as xenos raids and other calamities -- were fairly common. However, as the highest alert level was ordered throughout the Gothic Sector, few were deemed trustworthy enough to be privy to the true reasons why this heightened state of alert was ordered: the Warmaster Horus' rebellion against his father the Emperor. So it was that the worlds of the Cyclops Cluster and their billions of inhabitants turned ever inward in blissful ignorance of the dire events happening on Istvaan V. While security codes and targetting matrices had been changed swiftly as a matter of precaution, these measures would ultimately prove futile.

War came to the Cyclops Cluster in 006.M31. This was no massed assault by one of the Traitor Legions -- not yet -- nor even its allies amongst the Imperial Army, but a series of raids led by the forerunners of Horus' host. These attacks mainly focused on Imperial worlds isolated from immediate and major support, or left vulnerable by the growing turmoil of the galactic civil war. It is generally believed that Horus intended this both as a fully-fledged military campaign to weaken the Imperium and establish a power base from which to advance, as well as spreading fear and terror to further destabilise the wider Coronid Deeps, an action which Traitor infiltrators had already actively begun.

One of the most dreaded of these forerunners would soon prove to be the Ikon, an Eclipse-class Battlecruiser of the Sons of Horus Traitor Legion. The Ikon was responsible for the enforcement of the first Dark Compliance on the world of Gethsamaine Colonus. The Ikon penetrated the Gethsamaine System shortly after a Loyalist Emperor's Children frigate, the Malin Dawn, which was being investigated by Gethsamaine's two defence monitors. Emerging from the Warp alongside the 507th Attack Squadron of the Armada Imperialis, the Ikon quickly vanquished the monitors before destroying the planets astropathic relay and orbital defences, thus leaving the planet without major defences. As a thriving Civilised World, Gethsamaine was far from helpless and its sizeable Planetary Defence Forces and orbital batteries were soon ready to repel enemies, yet the Sons of Horus never did set foot on Gethsamaine, nor did they blast the world's cities to rubble from orbit. As soon as its work of destruction was completed, the Ikon made way for the system's jump point, but before she left, her captain left a message, a dark ultimatum which would be repeated across the Cyclops Cluster and in a hundred other star systems in the years to come.

With the destruction of Gethsamaine's astropathic relay, all pursuit was hopeless, the Ikon having long since departed until such time that Imperial naval command at Lascal or Dominica Minor could be informed. Soon isolated voidships and even entire convoys travelling through the northern regions of the Cluster began to declared first overdue and then were considered lost, no doubt destroyed or waylaid by Traitor marauders such as the Ikon. It was when attempting to warn the worlds of these regions that it was discovered that several frontier outposts could not be raised. The tale of Gethsamaine's fate was soon amplified and retold amongst those merchantmen, void-travellers and even Armada Imperialis-ships set to hunt down the Ikon and her companions. The seed of fear had been sown.

At the Eve of War

With the news of the Gethsamaine Dark Compliance growing more widely known, the Cyclops Cluster girded itself for war. On every world, vigilance and readiness levels were increased and hundreds of auspexes and astrotelephatic auguries began to survey the sky for any trace of the Horusite vessels. Incoming reports were all channelled through to the centralised Imperialis Armada command facilities at Lascal and Dominica Minor. As communication increased, the wider picture became apparent. The Ikon had reemerged from the Warp at Taracanis in the Manachean Commonwealth and offered its bleak words to the system's Imperial Commander, but not before having blasted the Manachea's docking station from orbit, sending thirteen thousand civilians to a fiery death. In the Grail Abyss, the observers from Shoar witnessed an orbital battle lasting several solar hours between several capital-class warships before both parties simply vanished.

Closer to home, in the Zavarich System a hulking Domar-class Mass Conveyor carrying enough processed nutritents to feed several million people simply disappeared without a trace en route to its assigned Warp transit point -- undoubtedly to cause civilian unrest or food riot elsewhere within the Imperium. On Moab, the ruling water-barons were confronted with a flare of insurrectionnist activities that led to a full-scale revolt, the mob chanting Horus' name. Only the instigation of planetary martial law and a bloody five-solar-week-long pacification pogrom restored order. Dark-hulled vessels were reported in the skies above Dark Haven, shortly before all contact with the planet was lost.

In the growing climate of scrutiny and distrust which had by now engulfed the Cyclops Cluster and other regions of the Coronid Deeps came -- finally -- long overdue news: word of the Drop Site Massacre on Istvaan V. Horus, the Warmaster, had destroyed three of the mighty Loyalist Space Marine Legions arrayed against him, while four more had joined him in rebellion. The reaction to this report was immediate: panic. On scores of worlds, planetary rulers now looked fearful to the skies, imagining the might of the Traitors ready to strike on their soil. Planets which had long been used to operating largely independently from each other now became isolationist and insular, in some cases even withdrawing their troops and tithes from the Armada Imperialis' general plan of defence, severely disrupting the Imperial war effort as they vainly sought to fortify their homes. On some worlds, the news of the Warmaster's crushing victory fanned the spark of ambition and revolt and factions long believed subdued reemerged to claim their world from the Imperium or their newfound allegiance to Horus.

In this state of turmoil, a number of strange and unheeded reports arrived at Lascal, Dominica Minor and even Port Maw. The most dire of these reports all came from the Grail Abyss, which only served to heighten fear in the neighboring Cyclops Cluster. On Keopsis, these reports stated, both Loyalists and Traitors were locked in combat and a desperate race to reach the underground cities before its sun's angry fires scorched the world's surface clean in its endless cycle of life and death. On Hialis, a mysterious and highly virulent plague decimated its inhabitants within a few solar hours of the passing of a previously unknown comet.

Above an unidentified Feral World in the vicinity of Fellwatch Keep -- one of a series of fortresses designed to watch the borders of the Coronid Prohibition Zone -- a mighty dragon-prowed Battle-Barge, perhaps once emerald and gold, now scorched cinder-black, was seen taking on supplies but vanished before any interceptor vessels could reach it. As the fear and paranoia gave birth to violence and civilian unrest, bloody pogroms and emergency laws were enacted, workers and inhabitants were conscripted into defence militias and transplanetary trade suspended. As a coherent structure within the Imperium, the Cyclops Cluster began slowly to unravel, each world looking after its own rather than finding strength in unity.

The Emissary of Mars

As was to become known much later, while the Ikon and her brethren began to sow fear and terror amongst the worlds of the Grail Abyss, during the closing quarter of 006.M31, the Cyclops Cluster received a very different type of visit: an official emissary from the Red Planet.

An ancient pict-capture of one of the Warmaster Horus's many Dark Mechanicum Ambassadors

Forge Worlds stand apart from the other worlds that make up the Imperium; their allegiance goes to the Fabricator-General of Mars and not to the Emperor on Terra; theirs is a pocket empire both distinct and intricately woven into the fabric of the Imperium. As hives of technological research and industrial might, their strategic value is unsurpassed except perhaps by the most important Hive Worlds, and their contributions to the Imperium are many: mighty warships, armies of cybernetically-augmented fighters and robotic battle-automata, supplies for the Emperor's armies, the destructive glory of the Collegia Titanica and many more. On a political level, however, Forge Worlds tend to be highly isolationist, more intent on meeting their next production quota and growth projections than worrying about the Imperium's security or future. While Dominica Minor could not hope to rival the military might of Mezoa, or the industrial output of M'Pandex, it was still considered the capital world of the Cluster, a position neither Mezoa nor M'Pandex had sought to usurp. While the alarm spread through the Cyclops Cluster, both Forge Worlds had continued to labour, taking little or no interest in the surrounding turmoil. Perhaps by design, Horus' forerunners had yet to strike a world of importance for the Forge Worlds' logistical supply lines, thus leaving them blissfully unaware of the wider situation.

Such it was that both Mezoa and M'Pandex received the visit of the Emissary of Mars. In both cases the ambassador presented itself under the name of Regulus -- which is widely believed to be an alias, as several entities bearing that name have been recorded in different locations at the same time. The original Regulus had been a senior Tech-priest of the Mechanicum of Mars who had given his domains over to Kelbor-Hal as to better roam the stars at the side of Horus Lupercal. This had been long before the betrayal at Istvaan V, and there could be very little doubt on whose authority this emissary now acted. Yet, Regulus was still a senior Archmagos of the Omnissiah and neither his presence, nor his words, could be discarded lightly. The Forge Worlds in the Cyclops Cluster were ignorant of the brutal Schism of Mars and that Kelbor Hal had thrown in his lot with the Warmaster, but it remains doubtful if further knowledge on that matter would have considerably influenced on the events to take place.

On M'Pandex the emissary was greeted with great reverence and courtesy and almost immediately led to a private audience with M'Pandex's ruler, the High Ourteka of the Golden Forge. The emissary identified himself as Regulus and bore dual patents of authority: the first from Horus and the second from the hand of Kelbor-Hal, the Fabricator-General of Mars, voice of the Omnissiah and Supreme Pontifex of the Mechanicum. To the High Ourteka, Regulus made both an offer and a demand; the demand was for fealty, as Kelbor-Hal -- their rightful leader -- bid them to obey the orders of the Warmaster as if they were his own and to offer up their armies, their craft and the fruits of their forges to Horus while offering shelter and supply to his warships and deny all these resources to those that had remained loyal to the Throne of Terra. Those Imperial Commanders not yet subjugated were already demonstratively squabbling amongst themselves, further convincing the High Ourteka that the way of stability, progress and obedience laid with Horus. If this had not been enough already, Regulus had not come empty-handed. He bore valuable gifts to sway the High Ourteka: STC technologies discovered during the late Great Crusade and never shared with the wider Mechancium; but most importantly Regulus made a promise, the promise that Horus would protect and sustain them, that Horus would free the Mechanicum from the strict tenures of the Treaty of Olympus Mons and give them the freedom to pursue the technologies and arcana they craved but the Emperor -- in his intolerable cruelty and ignorance -- had denied them.

On M'Pandex, a world which owed much to Mars, these offers were sufficient to sway the High Ourteka. On his sole authority -- without consulting M'Pandex's synod of Magi for confirmation -- the Forge World was pledged to the service of Horus. As was to be expected, some quarters resisted these new orders violently, but M'Pandex's history had been written in times of internecine conflicts such as these and any resistance was swiftly crushed by the High Ourteka's loyal Martian Skitarii and a detachment of sacred Battle Titans drawn from the Legio Mortis -- initially deployed to aid in the world's protection and now the High Ourteka's personal enforcers. This newfound allegiance was kept secret from Imperial authorities and outsiders while M'Pandex covertly girded itself for war.

The reception which greeted the Emissary of Mars at Mezoa, however, could not have been more stark in contrast than to that at M'Pandex. Regulus found a star system already geared for siege and conflict; his Warp runner was stopped at the outer edge of the system and forbade entry on the threat of immediate destruction. Mezoa had ever been a militant system, born in the ferocious wars of the Great Crusade and fashioned as much as a fortress as a centre of macro-industry, its Magi fiercely independent from their kin elsewhere and just as fiercely loyal to the ideals of the Imperium whose expansion they served. Here, simple obedience to the Fabricator-General would not sway the Pentarchy of Archimandrites that ruled this world. Forced to communicate via only the most primitive two-way Vox-circuit with a hulking Mezoan battle-sphere rather than directly with the Forge World, and under the condition that any attempt at other communication or the passage of data-djinn or other influence over the circuit would result in immediate annihilation, Regulus nevertheless argued his case and extended his demand of fealty and his offers.

In response, the Pentarchy made a blunt rejection of the Warmaster and a formal secession from the authority of Mars. Further, they called both Regulus and Kelbor-Hal apostates as well as blasphemers in the eyes of the holy Omnissiah and pronounced them and any that served under their command under sentence of death should they ever try to enter again the star system of Mezoa. As Regulus was forced to flee the system, a single word of judgement echoed through the still-open Vox-channel: "Heretek".

The Blockade of Mezoa

Mezoa's refusal was the first major setback for Horus, as the star system itself was not only nigh-impregnable, but the Forge World also commanded a number of valuable resource extraction plants and powerful allies such as the Imperial Knights of House Hermetika. This news could not become widely known less it became a rallying call for other Loyalist systems. So it was that Mezoa's denial was not widely broadcast but the system was almost immediately cordoned off by the Traitors.

Ancient Departmento Cartigraphicae chart of the Cyclops Cluster illustrating the Blockade of Mezoa

M'Pandex, Mezoa's long-time rival, had covertly been building up its military strength: its production capacities had been considerably geared up to feed the ever-growing hunger of Horus' armies and Loyalist and merchant voidships passing through its space were seized and impounded. Few of these ships had real military value, but their cargo holds held valuable resources to fuel M'Pandex's build-up of its own Taghmata. In this regard, the merchant vessels carried an even more valuable asset: its own crew and passenger. These were captured and forcibly converted into adsecularis slaves, to add to the M'Pandex Taghmata or to toil in whatever mine or forge needed reinforcing. Soon these captured ships were recrewed with men and Servitors loyal to M'Pandex and operated under a false flag to infiltrate and attack Mezoa's supply-lines, an action which also required the involvement of M'Pandex warships. In addition to this already sizable fleet, more shadowed and in some case unidentified forces -- obviously loyal to Horus -- began to invade the various star systems supplying Mezoa as to cut off the reluctant Forge World from its primary resources.

Wherever tactically sound and possible, the Mechancium of Mezoa resisted actively; although it steadfastly refused to marshal its full force and to leave the security of its own homeworld. The attacks on its far-flung outposts and mines were justly regarded as bait by the ruling Pentarchy of Archimandrites. Instead, Mezoa's garrison forces and outposts were ordered to resist until destruction. On far-flung mining stations and on the decks of mass transporter vessels, the forces of the two Forge Worlds -- always rivals but never before enemies -- clashed in mortal combat. Mercy was not to be found in either sides' circuit-augmented hearts and where the adsecularis cohorts of M'Pandex marched against the numerically fewer but more lethal centuries of Mezoa's Thallaxi. It is noteworthy that to outsiders this clash seemed to be a civil conflict between Mechanicum factions rather than the opening move in a wider game. On Jujya and Gunnar's Rock refinery stations burned, while on New Providance thousands of fleeing vapour-mill workers were caught between the advancing lines of Krios tanks and slaughtered needlessly in the withering crossfire of blazing energy weapons as both sides utterly ignored them. Believing this to be an internecine conflict between two rival Mechanicum factions, doubts and confusion stayed the Armada Imperialis' hand until it was too late. The conquered worlds and the valuable resources they harboured were mostly seized by M'Pandex to further aid their own expansion.

By the end of 006.M31, Mezoa had been almost entirely cut off from its colonies with the notable exception of Juiya. By now the system's outer edges were teeming with warships, like sharks having smelled blood in the water. Yet the enemy stayed its hand: Mezoa was still dangerous and too powerful and fortified to be taken, even by a force as large as a fully marshalled Expeditionary Fleet, but once effectively cut off from aid and from giving aid to others, the threat had been effectively neutralised. Time now played in favour of Horus and the Traitors as the blockade would continously weaken the Forge World's defences until such time as sufficient forces could be gathered as to definitely silence Mezoa. Mezoa's blockade would soon be noticed on other worlds, especially those depending on Mezoa's production capabilities. On Port Maw, the powerful Port Majoris of the Armada Imperialis situated in the neighbouring sub-sector, matters had steadily worsened -- without the supplies imported from Mezoa, Port Maw's stock of macro-ordinance shells was becoming dangerously low. Fleet command had begun formulating a plan of attack to break the Traitor blockade and address these matters, but events took a turn for the worse. Dire news reached Port Maw through garbled astropathic messages originating from Lascal in the Grail Abyss. Previously, a number of reports of worlds "going dark" had come out of this region and the stars bordering it, but to the authorities on Port Maw and Dominica Minor the Abyss' strategic value had been too small, too unimportant to squander its finite resource in warships while the proverbial wolf was already at their own door.

Now such parochial thinking had born dark consequences, and without warning, a massive fleet tore out of the Empyrean at the edge of the Lascal System, and there would be no time to rally reinforcements to meet it. Much of the strategic detail of what was to be Lascal's last broadcast had been lost to the soul-static of the Warp, but what images remained were clear enough: bleak warship after bleak warship, slab-grey and bone-white, stained and pitted with the scars of ancient battles and their recent acts of infamy. Alongside these were Warp-carried images of the death's head and the black sunburst, the scythe of the reaper. The Death Guard Legion had come for the Cyclops Cluster.

The Death Guard unleashed

"There is no darkness to be found between the void of stars, nor the deepest pits of the earth that equals the darkness of Mankind's deeds." "

—Excerpt from the suppressed Neo-Terran Credos

Orbital view of Lascal IV after its virus-bombardment by Death Guard Legion forces

When the XVII "Sun Dragons" deep range Cruiser squadron of the Armada Ultima finally forced their way through the Warp-turbulence which had dogged their attempts to reach Lascal in answer to their homeport's distress call, they emerged into a scene of still-burning carnage. The extensive war fleet mustered at the Armada's high orbital anchorage over the fifth world of the system had been a sizable force; some forty ships-of-the-line and more than a hundred Escorts and some heavier units in form of the Ozymandias, the Star Tamer and the Sceptre of Iron, three -Retribution-class Battleships that had proved their worth; and yet all had been blasted to ruins, some of the larger hulks still bleeding fiery plasma from their ruptured reactor cores or frozen air escaping from their lifeless and rent hulls.    

What was perhaps even more shocking was that further scans identified precious little wreckage as belonging to the enemy -- an entire war-fleet annihilated with barely any losses. This made for a most terrifying picture: an attack of such overmastering power, overwhelming strength and suddenness that resistance had barely had time to organise before being entirely wiped out. Further in, the Sun Dragons discovered that a new debris belt now surrounded their homeworld of Lascal V, whose origin was soon discovered: the remains of the high fleet anchorage station. Additional scans revealed the surfaces of the core worlds dense with the radiation of weapons-fire, the garbled echoes of distress signals and the characteristic fog of war.   

Mass graves

Carefully the Sun Dragons proceeded further in-system, as the area was still potentially dangerous due to active Void Mines, unspent ordnance and tumbling pieces of wreckage that could easily damage the Cruisers. Ever mindful of an ambush, the Cruisers continued, weapons ready for an attack that never came. Their Auspexes revealed what every man and woman amongst the bridge crew had feared: Lascal had not been merely invaded or conquered, but purged of any living soul and left for dead. The system's primary world, Lascal IV, once a burgeoning Imperial colony with a population numbering in the tens of millions, was now a poisoned orb, its atmosphere thick with toxic green and black strata betraying the tell-tale signs of mass biochemical bombardment.  

Solar Auxilia landing parties in full environment gear launched from the Sun Dragons' Cruisers to the palace of its Imperial Governor and several known defence bunkers. All returned ashen-faced, with the same tale of utter destruction to tell. The dead in their thousands covered the land, struck down in their stride by blistering airborne poisons and murderous nerve-agents. In those few places such as the Governor's palace, which had been sealed in time, a more direct hand had been required to destroy those seeking shelter within. Ferrocrete walls had been shattered by direct cannon fire, bulkhead doors torn from their mountings by the merciless gauntlets of Power Fists, and everywhere was rank slaughter and the litter of spent bolt shell cases, unmistakably Legiones Astartes in pattern.  

Most, however, had not been that lucky and had perished through over-exposure to the airborne necro-toxins; and as the landing parties would soon discover, even an Astartes constitution had proved insufficient against these vile poisons, for the bodies of a number of Iron Hands Legionaries were discovered amongst the dead. As if any more evidence was needed, the landing parties discovered the impaled and bloated corpse of Lascal's governor in an auditorium of his palace; there, above the cast down Aquila, flew a ragged banner bearing the death's head and black sunburst of Mortarion's dread Legion. 

Corpse of an unidentified Iron Hands Legionary discovered in a sealed chamber on Lascal IV -- likely an Istvaan V survivor; his damaged armour proved insufficient against the vile airborne toxins released by the Death Guard

As the Sun Dragons left the charnel house of Lascal behind them, news of what they had found quickly spread amongst the worlds of the Cyclops Cluster. Already fraying from each other in fear, pure terror now took hold among these worlds. At planets such as Endicott, Moravasis and San Pardor, news of the "Murder of Lascal" or the "Lascal Massacres" as they became swiftly known escaped to the general population -- perhaps purposefully leaked by agents of Horus and fifth-columnists already planted there by the Traitors' spy network -- civilian insurrections and rioting degenerated in open rebellion which toppled the Imperial authorities from power and left only chaos in their wake. But barely had similar dissent been put down in the orbital habitats of Dominica Minor, when news reached the seat of the Cyclops Cluster's notional political leadership, the Guildmasters, that the reaper's scythe had visited two more star systems, the mining colonies of Grist and Rabbasan, and left none alive. Both systems lay in a near direct path to the galactic South via the Warp-routes between Lascal and Dominica Minor. The Guildmasters now had precious little doubt that they would be next.  

Frantically, the panicked Guildmasters tried to invoke their Terran-bestowed primacy and call for fresh forces to be mustered from their dominions and vassal worlds, but their orders were mostly met with silence or scorn. Looking elsewhere for aid, they discovered with horror that the Mezoan blockade was now reinforced with dark-hulled warships of unknown origin. Worse yet, the Forge Lords of M'Pandex had turned from the Emperor's light and reached out to seize control of several worlds through their implacable cohorts of half-dead adsecularis troops, butchering any who would stand in their way.  

The horror only increased when they learned that Gethsamaine's Imperial Commander had bent knee before the Traitors, and delivered up his world without a shot being fired in its defence. Other worlds such as Vargas and Bleak Harbour had quickly mirrored his movement, while the feral natives of Zavarich had massacred their Imperial overseers and abased themselves before the Sons of Horus as if they were gods descending from the heavens. It was to the Guildmasters of Dominica Minor suddenly apparent that, with a surgeon's skill, the Cyclops Cluster had been dismembered and laid bare before onrushing death, as much by human weakness as by the sword of the enemy.  

Planets of the Cyclops Cluster

  • Dominica Minor - Dominica Minor was the only inhabitable planet in a solar system compromising several gas-giants and other planets whose alchemical atmospheres could readily be exploited. Dominica Prime was essentially an immense network of gas and alchemical refineries whose output flowed to the Mechanicum worlds of Mezoa and M'Pandex. With its output numbering in the billions of litres, Dominica Prime's wealth grew considerably, becoming the uncontested regional power in the sub-sector at the beginning of the 31st Millennium. While militarily speaking it could not rival such worlds as Mezoa or the Hive Worlds of the neighboring Manachean Commonwealth, Dominica Minor could boast its own substantial defence infrastructure, orbital shipyards and military vessels, which would all be ravaged by the Traitor Death Guard Legion in what was to be known as the "Death on Dominica Minor."
  • Bleak Harbor - Bleak Harbor is a Scavenger-type colonised world that was long ago known as "Auricalla" and whose location was included in ancient navigational datacores dating back to the Dark Age of Technology. In ancient tales and legends, Auricalla was described as a haven of civilisation and progress, an exemplar of Mankind's capabilities and genius and thus became one of many valuable civilisations for the newborn Imperium to contact. Yet when Imperial Explorators reached the planet, they would find only tumbledown ruins and semi-flooded wastelands seeded with the rusting wreckage of continent-spanning macro-machinery and the scattered bones of the dead. The ultimate fate of the lost civilisation of Auricalla remains unclear, it would seem, however, that no outside interference is to blame for Auricalla's fate: no war to topple its sky-scraping pyres, no hateful xenos breed to ravage its cities or epidemic to decimate its population. It would appear that society simply collapsed, regressed and tore itself apart as the result of some cataclysmic climate change that brought first inundations and then famine. No one knows for sure when this cataclysm happened, and it could very well be that Auricalla's demise dates back to centuries before the Imperium was even founded. By the time the Great Crusade reached this world, it had long been stripped of any valuable or technological remains. Nevertheless, the planet was colonised and used as a transit layover and port of last resort which contributed to give it its current name; salvation operations are still conducted in the vast ruins of the once magnificent cities, but Bleak Harbor makes for a dire place to live. Bleak Harbor is almost entirely covered in half-sunken ruins, swamps and rust-wastes. While nominally an independent world with its own Imperial Commander, Bleak Harbour lacks a stable population and those who live there are a desperate breed. Bleak Harbour's Imperial Commander has no notewothy resources to call upon and his world is indeed a dangerous place to live and one where the law is not enforced as it should be. Bleak Harbour's hinterlands and rust-wastes are a notorious haven for petty Hereteks, escaped prisoners and outlaws drawn there from all across the Cyclops Cluster. Bleak Harbour's situation was almost anarchic even before the Horus Heresy broke out, so it came as no great surprise that the world would bow to Horus of its own free will rather than risk further devastation.
  • Dark Haven - Dark Haven is an odd world, an exceptional if strange orb in an otherwise lifeless region of the Cyclops Cluster. The planet has been classified a Death World by Imperial cartographers because of its inherent toxicity to unaltered human life. Covered in vast forests of a fungal nature which absorb every iota of light in whose shadow hulking ambulatory mycolidae and other less well-understood predators lurk, this "dark haven" has nevertheless been colonised by the Lucien Mechanicum which established it as a Knight World. The planet was given over to the stewardship of House Orhlacc, once but a minor Knight House of Lucius that has since grown in power. Due to its untenable strategic position, Dark Haven was evacuated during the Horus Heresy, House Orhlacc seizing voidships that made its relocation to the Agathean Domain possible. Since the end of the Heresy House, Orhlacc has maintained a token force on their new homeworld of Wychval, but it is believed that the bulk of House Orhlacc has since returned to Dark Haven.
  • Endicott (Frontier World)
  • Gethsamaine - In the late 41st Millennium, Gethsamaine has become the capital of its own Sub-sector, but at the time of its inception in 942.M30, the world was still counted amongst those of the Cyclops Cluster. Gethsamaine Colonus was founded with expansion in mind, being located at the far edge of the Cluster and ideally suited for colonisation. In the sixty-four standard years before the outbreak of the Horus Heresy, Gethsamaine prospered and had reached the state of a proto-Hive World with much of its planetary surface given over to sprawling ferrocrete cities and manufactoria, boasting its own planetary defense troops and limited Armada Imperialis docking facilities. Gethsamaine was one of the very first worlds to surrender and submit itself to Dark Compliance after Horus' rebellion began. It also remains famed to the present day for being the location of the devastating "Raid on Gethsamaine" which heralded the beginning of the Age of Darkness, a continuous state of war between Imperial Loyalists and the Traitors that still endures ten thousands years after Horus' death.
  • Goth (Hive World)
  • Grist - Grist was a Mining Colony located to the galactic Southeast of Gethsamaine and whose location at the intersection of two major Warp-routes -- linking Gethsamaine to Mezoa, and Dominica Minor to distant Lascal -- had brought it prosperity. Like other worlds located on the second of these Warp-routes, Grist was invaded and utterly purged of life by the Death Guard on their slow march to Dominica Minor.
  • Gunnar's Rock - Like Jujya, Gunnar's Rock had been an outpost of the Mezoan Mechanicum dedicated to the production of Promethium and other chemical substances. Initial fighting before the establishment of the blockade of Mezoa inflicted severe damage to its refineries with few traces in Imperial Archives as to whom actually emerged as victor in this struggle. Loyalist resistance is believed to have been totally eradicated by the passage of the Death Guard Legion en route to Dominica Minor.
  • Jujya - Jujya counted as one of Mezoa's eldest and most established colonies outside of the Mezoa System, the Tech-priests having erected great Promethium and chemical refineries to produce the necessary fuel for their industries. Due to its closeness with its mother Forge, Jujya was considered very well protected until the events of the Horus Heresy would prove otherwise. Jujya remained Mezoa's sole colony to remain in contact with the parent Forge World during the entirety of the Blockade of Mezoa. It is unknown if the world suffered further invasions or attacks after a great deal of its refineries were destroyed or damaged in the initial engagements between the Taghmatas of M'Pandex and Mezoa.
  • Mezoa- Founded first as an outpost of the Lucien Mechanicum in 540.M30 before the Great Crusade took to the stars, Mezoa was recognised as an independent Forge World as soon as 813.M30, a rapid rise to power whose origins undoubtedly lie within the extremely rich planetary crust of their volcanic homeworld. Suffering repeatedly from the baleful attentions of the Mitu Conglomerate during its centuries of isolation, Mezoa became an extraordinarily war-like society, the planet being ringed by autonomous planetary defence batteries, kill-satellites and spatial mine fields that turned it into a nearly impregnable fortress. Brought peacefully into the fold of the Imperium after its rediscovery by the 7th Expeditionary Fleet, Mezoa soon dedicated its industrial might to the production of weapons, ammunition and warship hulls, notoriously becoming tasked with the supply and expansion of the naval base of Port Maw in the neighbouring Manachean Commonwealth. If in terms of pure production capacities Mezoa was outmatched by its ancestral rival of M'Pandex, it has nevertheless always been considered as preeminent among the Forge Worlds of the Cyclops Cluster and indeed the entire Coronid Deeps. While its Taghmata was, numerically-speaking, inferior to that of M'Pandex, Mezoa's forces almost entirely consisted of the advanced Thalaxii template, far superior to the Adsecularis used en masse by M'Pandex. Mezoa's last line of defence was constituted by their world's own volcanic nature, the high temperatures and geological instability rending deployment of Titan-class weaponry suicidal. All these factors would contribute to Mezoa's continued independence from the Traitors' growing shadow empire, even during the dark years of the Horus Heresy when forces loyal to the Traitor Warmaster would seek to conquer it. Several attacks were successfully pushed back, and the Traitors were give no other choice than to cordon off Mezoa and upheld its blockade for the entire duration of the conflict.
  • Moab - Moab is a chill and bleak but life-sustaining world which under other circumstances would likely not have been colonised by the Imperium. In Moab's case, however, two factors intervened to tip the balance in favor of human settlement: first the rarity of life-sustaining worlds within the Cyclops Cluster itself -- which made every such world, however bleak, far more valuable to the Imperium that it should readily be -- and second the planet's own location at the crossing of several stable Warp-routes, which readily made it the proverbial gate to the Cyclops Cluster. In the span of a few standard decades Moab became a populous world, first as a dormitory world for the Great Crusade's armies venturing into the northern reaches of the Ultima Segmentum, then for mining expeditions and settlers being shipped out to the Cluster's numerous mining colonies. This steady influx of people warranted the extension of Moab's administrative facilities until it not only became an independent world with a native population of several tens of millions of souls, but also the Cyclops Cluster's administrative Sub-capital. As the manpower relocated to Moab were often constituted from populations of recently Compliant or resistant worlds, conditions on Moab were particularly harsh, the population being controlled through force of arms and water rationing. Moab's sole resource of interest was its people, human "livestock" who could be used as manpower by both parties. The world suffered harshly during the Horus Heresy, its anarchic descent into chaos being commonly referred to as the "Sorrow of Moab." Despite this dark chapter in its history, Moab still counts as one of the many worlds in the Imperium's fold in the 41st Millennium.
  • Moravasis (Frontier World)
  • M'Pandex - M'Pandex is the Cyclops Cluster's second Forge World that -- although considerably older than its rival -- has ever stood in the shadow of Mezoa. Founded in the distant past when the Mechanicum launched vast Explorator arks out into space during the Age of Strife, M'Pandex suffered much through its isolation from the wider realms of Mankind, decaying and losing much of its technological knowledge until even its sacred God-Machines, the great Battle-Titans, fell into disuse. Discovered through luck by vessels of the 90th Expeditionary Fleet, M'Pandex joined the Imperium willingly, which heralded the Forge World's rebirth. Through major efforts of the Mechanicum of Mars, M'Pandex was restored, its production capabilities soon to rival those of far greater Forges such as Vannaheim or even mighty Lucius. Eternally indebted to Mars and its Fabricator-General in particular, the ruler of M'Pandex -- the High Ourteka M'andii of the Golden Forge -- would pledge his loyalty and that of his world to Kelbor-Hal and through him to Horus.
  • New Providence - New Providence was an arid world on the Warp-route leading to Taracanis whose surface had been given over to vapour mills and arcologies in which thousands of workers toiled. New Providence's exports almost went entirely to the benefit of the Forge World of Mezoa, which made it a prime target for the Mechanicum Taghmata of M'Pandex. In the ensuing battle, thousands of fleeing workers were butchered by both sides as the inhuman robotic battle-automata sought to confront each other, giving no consideration or quarter to the civilians trapped between their lines. It is unclear if New Providence was conquered in the initial assault of M'Pandex or the following invasion by the Sons of Horus on their way to Taracanis.
  • Rabbasan - Located at the northern border of the Cyclops Cluster, Rabbasan was but a simple Mining Colony when the Death Guard overran it in 006.M31, poisoned its atmosphere and killed its entire population -- barely worth a footnote in the great book of atrocities committed by the XIV Legion during the years of the Horus Heresy.
  • San Pardor (Frontier World)
  • Vargas (Civilised World)
  • Zavarich - Zavarich is one of the few Agri-worlds to be located within the Cyclops Cluster and whose growing importance within the Cluster promised it a rich and bountiful future. Zavarich has always been a Feudal World, even before it was brought bloodlessly into Imperial Compliance by the 611th Expeditionary Fleet in 876.M30. Having rallied to the Imperial fold, Segmentum authorities decided to turn Zavarich into an Agri-world, its production centered on high-yield tharac-wheat with Grox and Macro-krill herds as a secondary complement. In the decades following its Imperial Compliance, Zavarich became increasingly more important for the Cluster's economy, which motivated an influx of colonists and agri-workers being directed to the planet to further increase its productivity. A census conducted just before the outbreak of the Heresy cited Zavarich's population at just under three million souls, with perhaps as much as a quarter of them being non-natives. This caused significant unrest as the colonists often took over management roles, thus supplanting the natives, but more importantly the native population stubbornly adhered to their ancient autochthonic cultic belief systems whereas the colonists were all strong adherents of the Imperial Truth. It is unclear by which means Zavarich's native population was corrupted by Horus' agents; however it quickly became apparent that this was the case when the Ikon entered Zavarich's skies. The arrival of the Sons of Horus' Strike Cruiser seemed to have been the long-awaited signal for the local population to rise up against the Imperial faction and utterly slaughter them. Rumour has it that when the Sons of Horus descended on Zavarich, the locals abased themselves before the towering Astartes as if they were gods, a veneration that goes against every tenet of the Imperial Truth.

Notable Military Campaigns

  • Xenocides Campaigns (Unknown Date.M30) - Having suffered previous attacks on its homeworld, the Mezoa Mechanicum periodically launched xenocide campaigns against the xenos of the Mitu Conglomerate. As a side-effect of these ventures, the Mezoa System itself is heavily reinforced and fortified to ward against any reprisal attack from the Mitu.
  • The Mitu Eradication (Unknown Date.M30) - The Mitu Eradication was an Imperial xenocide campaign directed against the xenos pocket-empire known as the Mitu Conglomerate. While the Mitu Conglomerate's core-worlds were mostly located in what had been the Manachean Commonwealth and the Cyclothrathine Holdfast, many worlds of the Cyclops Cluster also suffered from the Mitu's rule. The war against the Mitu Conglomerate was foremost a naval war, constituted by savage boarding engagements between Imperial and xenos ships. Once naval superiority was ensured, planetary assaults were then conducted to liberate the human worlds. It is a testimony to the strength of the Conglomerate that several Expeditionary Fleets drawn from the Solar Auxilia Cohorts and no less than three Space Marine Legions were necessary to bring their baleful rule to an end. The decisive battle was fought in the Manachea System, on Manachea Lux, while the Cyclops Cluster saw only minor engagements. It was after the Mitu Eradication that contact was again made with much of the Cluster.
  • The Gethsemaine Dark Compliance (006.M31) - When a ship of the Traitor Legions, a Gladiator-class frigate of the Emperor's Children penetrated into the Gethsamaine System, Gethsamaine's military authorities quickly despatched its two defence monitors, the Gaius Herab and the Brazen Bull, to investigate the matter. The III Legion's ship was identified as the Malin Dawn, a Loyalist ship that had tried to break away during the Istvaan III Atrocity but that would be boarded and destroyed from within while in the Warp. The ship's Navigator would see it get to its destination before her strength failed her, thus leaving the Malin Dawn a ghost-ship. While investigating, the Gaius Herab and Brazen Bull were attacked and destroyed by the Ikon and her Escorts which quickly turned their weapons on Gethsamaine's orbital batteries and astropathic relay, thus severely disturbing Imperial navigation and communication channels. Gethsamaine Colonus itself was spared the depredations of the Sons of Horus, but was subjugated following Horus' victory in the region.
  • The Blockade of Mezoa (ca. 006-011.M31) - Following its refusal to join forces with Horus, the Forge World of Mezoa was attacked by both the forces sworn to the Warmaster and the fleet of its erstwhile rival, the Forge World of M'Pandex. One by one, Mezoa's extra-planetary domains are invaded, conquered and where necessary, destroyed. By the end of 006.M31, only Mezoa and Jujya still resisted in a secure enclave that had been cordoned off from the wider sub-sector by military vessels of M'Pandex and reconverted merchant vessels. This blockade was upheld through most of the Horus Heresy and considerably bolstered after the infamous Treachery at Port Maw incident by turncoat vessels of the Armada Imperialis. Blockading the system would, however, not suffice and several attacks were launched on Mezoa to deal with the menace it still represented. The first of these more severe attacks -- led almost entirely by Dark Mechanicum elements from M'Pandex -- was to fail spectacularly as the Magi of Mezoa succeeded in turning their world's fiery heart against the invaders, collapsing the fragile crust under the enemy landing zones and hurling island-sized chunks of magma into orbit against the vessel supporting the invasion. The enemy commander, a Traitor Archimandrite, is reported having been torn to ribbons by a mysterious warmachine dubbed "the dragon" which was rumoured to have been retrieved from the black sands of Istvaan V; although the details and the reasons as to its presence on Mezoa remain a total mystery. Mezoa's continued defiance would eventually request the involvement of Legiones Astartes personnel in the form of several armoured battalions of the Death Guard Legion, the grim sons of Mortarion. These attacks would not be successfully pushed back until the avenging armies of the Imperium ventured forth during the time known as the Great Scouring.
  • The Orhlacc Exodus (ca. 006-007.M31) - Trying to sway the reputed House Orhlacc into Dark Compliance, the Rogue Trader Charid Udine was exterminated with his retinue by the vengeful Knights of House Orhlacc. Dark Haven's few defence lasers -- hidden deep beneath the fungal canopy of their world -- exacted a heavy toll amongst the Rogue Trader's flotilla, while Charid Udine's own vessel, the ruby-hulled galleass of war, Hammer of the Deep, is captured by the loyal Knight House. The Lord Seneschal of Dark Haven reported the incident to the cluster's authorities but received only platitudes in reply. With the Forge World they owed fealty to already being blockaded, Valdemar Orhlacc ordered the planet to be secretly abandoned, a fact that was deliberately kept hidden from Loyalist and Traitors alike. House Orhlacc's exodus was only noticed several solar months later when the Khabir, a Lunar-class Cruiser on patrol from Dominica Minor, reported Dark Haven deserted. Many thought House Orhlacc had simply been destroyed or had vanished entirely, but these rumours of their demise were all to be proven wrong as the Knight House had not perished in their long voyage, but had successfully found shelter within the Agathean Domain. House Orhlacc would also once again take to the field of battle almost two standard years later during the famed Liberation of Numinal, where their decisive intervention heralded an important Imperial victory.
  • Civilian Insurrections (006.M31) - As news of the Murder of Lascal reached the Cyclops Cluster, fifth-columnists and spies of the Warmaster Horus purposefully spread the tale amongst the civilian population, which results in civilian unrest and rioting. While on Dominica Minor these disturbances are held in check, the terrified mob seized power on such worlds as Moravasis, Endicott and San Pardor and these planets descended into anarchy.
  • The Reaping (006.M31) - In a deliberate act of terror -- to disseminate fear within and without the Cyclops Cluster -- the Death Guard descends on such low-population worlds as Rabbasan and Grist, exterminating their people and poisoning the ground.
  • Death on Dominica Minor (006.M31) - Having ravaged every star system in its path, the Death Guard finally reached Dominica Minor, the military and economic heart of the Cyclops Cluster. When the Death Guard's fleet emerged from the Warp they bluntly waded through the outer minefields, using captured mining barges as fire ships to detonate the mines. Hugely outgunned, Dominica Minor's defence fleet clung to its orbital fortifications and was already on the point of surrendering, unloading everything it had at the Traitors, whose Void Shields buckled and heavy armour was scorched but only rarely penetrated. On command, the Death Guard fleet, now almost in boarding range, turned and unleashed a single devastating broadside which annihilated the defenders. When it came, the ground assault displayed the typical brutality of the Death Guard and the focus of a Legiones Astartes strike. The first wave targetted communication towers, defence batteries, militia bastions and orbital relays, silencing those weapons that could pose a threat to the ongoing assault. Then came the heavy landers and the bulk of Mortarion's force. Unhurried, 30,000 Legionaries marched to war, easily crushing the militia gathered against them that outnumbered them twenty or thirty to one. Yet the defenders' numerical superiority counted for nothing as their weapons were wholly inadequate to fight members of the Astartes. As the retreat became a rout, the Death Guard made no distinction between fighters and civilians, unleashing bursts of Bolter-fire or shelling hab-blocks with aspyx-gas, or running the enemy down with their tanks. Dominica Minor had been marked for massacre. Only two places truly resisted the onslaught, first the planet's primary starport where colossal mining machines and industrial-grade heavy Servitors had been repurposed as makeshift war-machines and second, the heavily fortified entrance to the ruling Guildmasters' personal shelter were their well-equipped retainers and the few stranded Loyalist Space Marines had decided to make their stand. To break the stalemate at the starport, Mortarion unleashed the gathered might of House Makabius, the Knights eager to prove their mettle in battle. While their Knights made short work of Servitors and militia, the towering mining machines could still crush them easily but they were cumbersome and slow to handle. Using their Knights' mobility against the lumbering mining-Titans, House Makabius easily overcame this last line of resistance and soon the starport was bathed in the blood of its defenders. At the Guild Hall, news of the presence of Legionaries from the Salamanders goaded Mortarion to lead the attack personally, duelling with one of the last remaining Dreadnoughts of this broken Legion but which had no true chance to defeat a Primarch. With his huge scythe jutting from the Dreadnought's sarcophagus, the defenders of Dominica Minor were defeated. What few survivors remained were mercilessly hunted down and killed, including the valiant Salamanders. It had taken the Death Guard less than three solar hours to murder an entire world.
  • The Sorrow of Moab (006.M31) - The Sorrow of Moab describes the descent into anarchy of the administrative sub-capital of the Cyclops Cluster, following the arrival of the Sons of Horus Cruiser identified as the Ikon. Although no shots were fired and no troops ravaged Moab, the world's Imperial Governor was quick to surrender. With no answer coming from the anonymous captain of the Ikon, the tension became unbearable and sparked into violence as an armed mob of civilians lead by Secessionist muster-barons stormed the Governor's palace and slew Malthus Grange. This act greatly pleased the Sons of Horus, who encouraged the violence. In the span of a few short solar nights and days of murder, rampage and massacres, Moab descended into anarchy, killed by its own people. Those that survived would then join Horus' camp.
  • The Battle of Gethsemane (151.M40) - The Battle of Gethsemane marks the beginning of Lord Admiral Ravensburg's counterattack during the famed Gothic War. During this prolonged naval battle that was to take place over several solar weeks, Lord Admiral Ravensburg personally led almost the entire might of Battlefleet Gothic against a splinter-fleet of Abaddon the Despoiler's Chaos Armada. The tables were, however, turned when a second Chaos fleet entered the system and tipped the balance of force in favour of the Traitors. Using the stellar dust fields to his advantage, Lord Admiral Ravensburg succeeded in forcing the Chaos fleet to fight his own fleet head-on where the Chaos warships suffered greatly. Trying to escape, the inopportune appearance of an Eldar fleet trapped the Chaos fleet between two gun lines which resulted in a major Imperial victory.


  • Battlefleet Gothic Rulebook, pp. 94-95, 122, 145, 159
  • The Horus Heresy - Book Four: Conquest, by Alan Bligh, pp. 22-35, 66-68
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