Port Maw is an ancient artificial world that has been turned into one of the great harbours of the Imperial Navy by human ingenuity. Located in ancient times at the very border of the Segmentum Obscurus and the Ultima Segmentum in what was then known as the Manachean Commonwealth, today Port Maw lies within the famed Gothic Sector of the Segmentum Obscurus and even has given its name to an entire sub-sector.

Since its inception during the Great Crusade, Port Maw has always belonged to the Imperial Navy, or rather to the Armada Imperialis which preceded it. With the tactical need to establish second-line defence forces to protect the heavily industrialised and populated regions of the Manachean Commonwealth and the Cyclops Cluster Sub-sector, Port Maw was rapidly established as a great mustering and supply point for Imperial vessels heading to the Imperium's northern border.

Over the millennia, Port Maw has grown into one of the biggest starports of the Imperium, being perhaps only surpassed by the great Segmentum Naval Bases of Bakka, Hydraphur, Kar Duniash and Mars itself. It still serves as the main port of attachment, Segmentum fortress and headquarters of Battlefleet Gothic -- itself one of the Bastion Fleets -- while Segmentum Headquarters lies on Cypra Mundi. It is also at Port Maw that most of the reserve ships of Battlefleet Gothic are located, mothballed until events dictate their return to the frontlines.

Through its proximity to the Eye of Terror and the need to defend the Cadian Gate, Port Maw is nearly perpetually on a war-footing, despatching relief convoys to the other Bastion Fleets stationed at Agripinaa and Belis Corona, patrolling along the edges of the Eye of Terror, answering countless planetary distress signals and generally trying to keep the Forces of Chaos at bay. Through its long and glorious history, Port Maw has come under attack several times, most notoriously during the Horus Heresy era in the infamous Treachery at Port Maw Incident and far more recently during Abaddon the Despoiler's 12th Black Crusade, more commonly known as the Gothic War.


Port Maw was discovered orbiting the world of Aestellica during the Great Crusade by captains of the 60th Expeditionary Fleet under the overall command of Lord Marshal Ireton MaSade, whose family would go on to rule over the Hive World of Agathon and its Agathean Domain. Port Maw was not formed naturally but is an entirely artificial planetoid of ancient provenance, built in times immemorial that Imperial historians believe to even predate the rise of the Aeldari Empire.

Since the dire events in the Vidar System of 926.M41, several voices have been raised speculating that Port Maw may well have been an earlier spoiled or sabotaged attempt by the race known as the Necrons to create a World Engine, although no physical evidence currently supports these theories. However, given the presence of other artefacts of pre-Imperial technology maybe dating back to the War in Heaven across the Segmentum -- most tellingly the Blackstone Fortresses and the Cadian Pylons -- unknowingly repurposed by the Imperium, this theory could still prove true.

Port Maw owes its name to a five-hundred-kilometre-wide aperture in its planetary crust that roughly resembles a fanged maw ready to bite, an apt name given the planetoid's peculiar appearance. This means that the interior of the planetoid is entirely hollow, thus offering an unsurpassable level of protection for sensitive industries such as ship-forges or munition manufactoria. This potential was quickly realised by the Armada Imperialis officials who accompanied the 60th Expeditionary Fleet and rapidly defended their claim.

Port Maw's existence as an Armada Imperialis Port Majoris began in 001.M31 when construction on the hollow inside of the planetoid was begun. At that time, the Great Crusade was still heading for the galactic north, fully expecting to press on in that direction before encountering the intergalactic void that would form a natural border for the Imperium.

Other Armada Imperialis facilities, most tellingly the Fleet Anchorage Point at Lascal in the Grail Abyss, designed for resupply and logistical support, also entered the construction phase. As the Great Crusade reached the proverbial dead-end in the Grail Abyss, work on the Port Maw facilities nearly stopped but was soon continued as new threats behind the lines of the Great Crusade emerged. In particular, Orks still periodically plagued the region, although they had been driven away from the Grail Abyss.

The nature of the Imperium slowly changed, as the Great Crusade had nearly accomplished what it set out to do -- conquer the galaxy for Mankind -- but now other needs arose. The vast new domains of the Imperium had to be policed and protected; the Coronid Deeps had to be secured. This would be Port Maw's new purpose. In each of the Segmenta Majoris outside the Segmentum Solar, a Port Majoris would be erected: a home base for permanently detached Battlegroups and where Expeditionary Fleets or other Imperial expeditions could resupply and repair.

In parallel, whole armies of Imperialis Auxilia would also be stationed at these key systems as the armadas would serve as both rapid-reaction forces and deep-range space patrols to respond to sudden threats such as civil unrest, rebellion or outside attack. Soon the outer planetoid and indeed the entire star system were given over to other space-faring installations: battle stations, trans-orbital dock yards, and provender belts.

Although far from completed, Port Maw began operation as a logistical way-station, supply base and mustering point. It also boasted its own Battlefleet, the Port Maw Armada under the command of Grand Admiral Ospeus LaBray. The Port Maw Armada would first and foremost be defence-orientated, designed to dominate "small wars" and keep the Emperor's Peace. On paper they easily outgunned and outmatched any given Expeditionary Fleet, even the vaunted 63rd Expeditionary Fleet led by the Warmaster Horus himself, but the ships of the Port Maw Armada were often scattered over considerable distances of space performing their duties.

As such, this armada was mainly constituted of ships-of-the-line, Cruisers and assault vessels for patrol duties and Escorts like Frigates and Destroyers for voidship escort duties, pirate-hunting or the tracking of lone enemy vessels. By nature, the Port Maw Armada fielded fewer capital-class ships than an Expeditionary Fleet. That did not mean, however, that these Segmentum Armadas fielded no such vessels.

To the contrary, most of the capital ships they possessed were still front line-worthy but had been relegated to second-line duties because of the emergence of better designs or the commission of those classes which needed less maintenance time. Both factors, however, did not hinder the Segmentum Armadas, as they were designed to operate from a base rather than endlessly roam the galaxy like an Expeditionary Fleet would. As a result, the Port Maw Armada could field several of the powerful if support-intensive Goliath and Legatus-class Battleships, which depended more readily on supply lines and manufacturing capabilities than the Gloriana and Victory-classes that now constituted the fleets of most Space Marine Legions.

Grand Admiral Ospeus LaBray's flagship, for instance, was the Triumph of Reason, a huge fleet control vessel that had been reforged from the hulls of two crippled Legatus-class Battleships, a starship that could rival the best-known vessels of the Great Crusade. The Triumph of Reason was a mobile command post, a warship capable of coordinating the actions of an entire Segmentum Fleet and that would prove its mettle in more than one battle. In total the Port Maw Armada fielded some one hundred and seventy capital ships or ships-of-the-line with nearly a thousand lesser warships and Escorts at its disposition. By all accounts this was a sizable force for the time.

Horus Heresy

When the Warmaster Horus revealed his ambition on the plains of Istvaan III, Port Maw was still under construction. It was, however, operable in limited fashion as a supply-point for those fleets that would eventually sail forth to confront the Renegade Warmaster and those Traitor Legions that had sided with him. The Port Maw Armada, however, would take no part in the following campaign. Under orders from Horus Lupercal -- then still believed to be the loyal Right Hand of the Emperor -- the Port Maw Exercitus had sent out much of its might to support distant warzones or on extensive and far-flung patrols, thus scattering most of its effectives across the sector and beyond.

Some battlegroups had been temporarily reassigned to warzones and conflicts in other Segmenta, while some warships assigned to patrol were purposefully led into ambushes or distant corners of the galaxy never to be seen again. Port Maw would, however, be able to resupply some of the Loyalist Space Marine fleets that were sent to confront Horus, and both the fleets of the Iron Warriors and the Raven Guard stopped at Port Maw for a final resupply before sailing forth to what was to become the Drop Site Massacre.

Both fleets received updated reports on Port Maw's status as well as new security codes clearing their advance. Deeming their routine codes and identification protocols unsafe, the Loyalist authorities had changed them and placed their own defences and troops at readiness, but all these measures were deemed as mere precautions. Nobody truly expected the Traitors to emerge victorious against the might of eight of the Emperor's Legions of Space Marines.

In the closing days of 006.M31 news of the Drop Site Massacre finally reached Coronid Thule and caused a flare of panic amongst the ruling elites of the cluster. Having to rapidly reevaluate their situation, Loyalist Imperial Commanders soon found out that some worlds had already "gone dark," all communication lost and having likely been occupied or ravaged by the Traitors.

The first real warning of impending doom, however, came not from the Cyclops Cluster or even the Grail Abyss, but Istvaan V itself. Isolated or in very small groups, ships hailing from the Istvaan System and belonging to the Shattered Legions -- the Raven Guard, the Iron Hands and the Salamanders -- found their way to Port Maw or other worlds such as Lascal and Dominica Minor, bearing with them the terrible news of their defeat. All these arriving vessels were battle-scarred, wounded and in some cases barely space-worthy, yet only the most damaged stayed in the Manachean Commonwealth or in the Cyclops Cluster -- nearly no Legiones Astartes chose to stay behind and fight the Traitors; most chose to retreat further after having accomplished emergency repairs or in some instances changed ship.

Soon, however, the worlds of the Cyclops Cluster and the Manachean Commonwealth were girded for war. They found enemies already amongst them, lone outriders to the Warmaster's forces such as the dreaded voidship Ikon were sighted imposing Dark Compliances on ill-defended worlds, but most notoriously Mezoa. The mighty Forge World supplying Port Maw with much of its macro-ammunition was blockaded by unknown vessels and the entire fleet of its old rival from M'Pandex.

Foreseeing a shortage of advanced munitions and macro-weaponry, the authorities at Port Maw were beginning to formulate a response to break through the blockade when dire news reached them from the edge of the Grail Abyss. Lascal, an Armada Imperialis High Anchorage with its own sizable fleet to defend it -- nearly forty ships-of-the-line and three Retribution-class Battleships, the Sceptre of Iron, the Ozymandias and the Star Tamer -- had been utterly destroyed. Their sole contribution to the war would be a garbled warning the astropaths had much trouble to decipher: the Death Guard Legion was heading for the Cyclops Cluster.

Faced with this emerging threat, the Port Maw Armada could not commit its strength to aid the beleaguered world of Mezoa, nor would it risk an open battle for the ultimately non-strategic Grail Abyss. Reaching out for what ships of its own fleet it could, the Port Maw authorities tried to assemble its might to face the enemy, recalling every warship they made contact with while despatching a squadron of deep-range Cruisers, the XVII "Sun Dragons", to investigate matters at Lascal. The Sun Dragons reported that the Lascal High Anchorage and the fleet that had been stationed there were now nothing more than a debris belt orbiting a murdered, ravaged and poisoned world.

Solar Auxilia landing parties in full hazardous environment gear launched from the Sun Dragons Cruisers to the palace of Lascal's Planetary Governor and several known defence bunkers all returned, ashen-faced, with the same tale of utter destruction. 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 Imperial Governor's palace, which had been sealed in time, a more direct hand had been taken to destroy those huddled 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.

As if any more evidence was needed of the perpetrators of this atrocity, in the auditorium of the Imperial Commander, above the cast-down Aquila and impaled in the bloated corpse of the man who had ruled there in the Emperor's stead, was a ragged banner bearing the death's head and black sunburst of Mortarion's Death Guard Legion -- a dire warning to those that would refuse to bow to the Warmaster Horus. As the Sun Dragon squadron left the charnel house of Lascal behind them, news of what they had found quickly spread, and in the star systems of the Cyclops Cluster, already fraying apart from each other in fear, pure terror now took hold. The "Murder of Lascal" as it soon was known, spurred defensive measures even further. The Cyclops Cluster and Manachean Commonwealth prepared for an inevitably bloody war. It was then that the cruel whim of fate intervened.

Enemies Unlooked For

Amongst the multiple unpredictable threats that can emerge suddenly and ravage worlds and entire star systems, few are so dreaded as the appearance of a Space Hulk. These conglomerates of trapped asteroids, planetary debris and wrecks of long-lost starships randomly emerging from the Warp are often populated by hostile xenos lifeforms, most notoriously the savage species of the Orks.

Drawn perhaps by the strong astrotelepathic signal of the Commonwealth's principal astropathic relay -- the relay at Vlorlath Srader -- or perhaps simply thrown off-course by an unfortunate Warp Storm, a vast Space Hulk carrying with it its own fleet of ramshackle voidships emerged in the Vlorlath Srader System, on the ill-defended Commonwealth's eastern flank. In accordance with the principle of the Coda Navis, this new threat was baptised by the name of Red Polyphemus.

Space Hulk by Zen Master

Pic-capture of the Red Polyphemus exiting the Warp.

Although far from unknown, the Orks posed at best a seasonal nuisance in the Coronid Deeps, their true strength broken in the days of the Great Crusade, yet the Red Polyphemus and the uncounted Greenskin multitudes it harboured constituted the most sizeable migration of Orks for nearly thirty Terran years. Tens of thousands of mutated Orks and gyre-worms had already laid waste to the vital astropathic relay, meaning that the Commonwealth and Port Maw were now cut-off from communications with the Segmentum Solar.

Worse yet, the Orks were now scrambling over Vlorlath Srader whilst the Space Hulk itself inexorably ploughed deeper into the system. Nobody could have foreseen this turn of events, but it was soon whispered that a terrible yet brief Warp Storm had been witnessed shortly beforehand which may have altered the course of the Hulk.

Unable to simply ignore a threat such as an entire Space Hulk sprawling with Orks going on a rampage within the star systems they were sworn to protect, the Port Maw Armada despatched a sizable portion of its strength, both in ships and in men, to the Vlorlath Srader System. The relay was undoubtedly gone, but the planet could still be reconquered, for letting the Orks gain a foothold in the Manachean Commonwealth would only bring about future calamities.

Standard procedures in dealing with a Space Hulk dictate the Hulk being boarded, preferably by Astartes troops, and destroyed by the planting of seismic charges which would then be detonated from afar, thus ripping apart the Hulk from the inside. This option was, however, not available to the Battlegroup despatched from Port Maw, firstly due to its lack of Legiones Astartes assistance, and secondly because while the Solar Auxilia were fully equipped and trained for such operations, their firing discipline and superior coordination would count for nothing inside the meandering and tight corridors of a floating wreck like the Red Polyphemus.

Lastly, the Solar Auxilia would be direly needed to fight against the Warmaster's forces once the threat of the Orks had been neutralised, and could therefore not be sacrificed in a desperate gambit. The Red Polyphemus would thus need to be destroyed at gun-point, the Armada Imperialis vessels having to get in perilously close before unleashing close-range bombardments to rip apart the shattered planetary rocks and derelict ancient shipwrecks that made up the Space Hulk.

This was inherently dangerous as the Imperial ships exposed themselves not only to the long- and short-distance fire from the Orks manning the Space Hulk's guns, but also because they offered easy targets for Ork suicide-runs and boarding assaults led by the barbaric xenos that infested it like vermin and whose ships -- despite looking like heaps of junk -- were utterly lethal.

Without the elite Solar Auxilia Cohorts of the Port Maw Exercitus, dealing with the catastrophe at Vlorlath Srader would simply not have been possible, both in terms of counter-invasion of the star system's colony worlds, and the defence of the taskforce attacking the Ork Hulk. The campaign to stop the Red Polyphemus would, however, be far longer than anticipated, the Hulk's fabric being unusually resistant to the fleet's bombardment.

It wasn't until the closing days of 007.M31 that the Space Hulk finally began to fragment and victory was assured. However, this victory had entailed a butcher's bill in Imperial lives and ships, all that the Commonwealth's defence against the Traitors would subsequently lack. Worse yet, the Battlegroup had used up nearly all of its complement of macro-ammunition which would now be nearly impossible to refurbish as the main provider of these goods, Mezoa, was still blockaded. As a result, fresh troops intended to face Horus' forces were now worn-out or missing. Many warships would need extensive repair before returning to battle, and when news of the fate of Lascal and Dominica Minor reached Manachea and Port Maw, the defenders' morale dwindled still further.

Isolated from the Segmentum Solar through the loss of the Vlorlath Srader relay and in no shape to come to the aid of Mezoa, the Port Maw authorities turned to those allies it still could readily reach, those worlds like Numinal and Agathon in the Coronid Reach. Even the insular Mechanicum of Cyclothrathe declared ready to send troops and vessels to the grand muster of Imperial forces Grand Admiral LaBray had called.

All the while the Port Maw Armada had fought the Red Polyphemus, fugitive ships from the Cyclops Cluster had reached the Commonwealth, telling grim tales of their worlds' demise before slowly ebbing away. This could only mean that an attack on the Commonwealth was imminent. Grudgingly the Imperial Commanders of Numinal and Agathon were made to agree to despatch many of their ships to Port Maw, fully aware that if Port Maw and the Commonwealth fell, they stood little chance in turn.

Orders for general mobilisation were issued, the final stages of emergency plans enacted, defences on the eastern border heavily reinforced and known stable termini of Warp routes to the Cyclops Cluster heavily trapped with Void Mines. Control frequencies that had been proofed against treachery were completely replaced by new ciphers and encryption djinns (artificially intelligent encryption programs). With much of the Armada's strength still mobilised in the Vlorlath Srader System, patrol ships were recalled and assembled at Port Maw, readying themselves to face what would have once been an unthinkable threat: the massed attack of the Death Guard from the dead silence that now reigned in the Cyclops Cluster.

It was, unfortunately, exactly as Horus had planned.


For all intent and purpose, the Aestellica System had become a fortress, a citadel of Imperial might that would hold out against the Traitor -- or so the Port Maw authorities at least thought; for they had failed to anticipate that even the mightiest fortress can fall from the inside. Unbeknown to Grand Admiral Ospeus LaBray, the Imperial muster at Port Maw had been infiltrated by agents of the Warmaster.

In a conspiracy of unforeseen magnitude whose many layers and ramifications had stayed hidden, a shadow network had established itself, worming its way into nearly every sensible position. Even the Grand Admiral's own flagship, the imposing Triumph of Reason, harboured countless Traitors as did many other vessels that had heeded the admiral's call to arms. Chief amongst these Traitors was the Archmagos-Astral Leit Mercuric, Cyber-Ordinator of Port Maw's Panopticon.

The Mechanicum Astra Panopticon tower was a ten-kilometre-high transmission and broadcast tower, whose powerful antenna pierced the sky at the southern pole of the planetoid. The Panopticon regulated in-system traffic so as to ensure that no collisions impeded the daily work of the countless vessels, transports, supply ships and tenders that Port Maw needed to function. It also doubled as a central communication hub for the Port Maw Armada, relaying fleet orders and checking navigational coordinates.

There a secret countdown was set in motion, designed to coincide with the arrival of the Sons of Horus' vessels in the neighboring Manachea System. As the countdown irremediably reached zero, the hand of the Warmaster was revealed. No warships of his Legion or the feared Death Guard presented themselves at the outskirts of the system, only those forces of the Mechanicum and the Armada Imperialis secretly sworn to Horus would deliver Port Maw into his waiting hands.

Suddenly, malignant data-djinns filled the communication channels, burning out Vox-channels, shutting down Auspex arrays and overcoming the Machine Spirits of lesser Escorts and merchantmen vessels, altering their course to crash, sending Plasma Reactors into overdrive or triggering unforeseeable accelerations which turned the unprepared human crews into a fleshy pulp. The larger warships of the Armada suffered little from this cyber-attack, but as a result of the mayhem the fleet was in a dire state of chaos, capital ships deprived of communication and Escort craft scrambling for orientation.

The cyber-attack was the signal Traitor agents and fifth-columnists had been waiting for to spring into action. All across the fleet mutinies and revolts erupted amongst the Port Maw facilities, the ships' crews and even the Triumph of Reason’s and the Kurga’s decks. Grand Admiral Ospeus LaBray's elite Veletarii Life Guard barely stopped an assassination attempt on the Armada's commanding officer, while on some ships purposefully spared by the data-djinns weapons opened fire on their "comrades," their Traitor captains seizing on the confusion wrought by the data-djinns to inflict maximum damage on Loyalist ships.

Everywhere, battle between Traitors and Loyalists was joined. Port Maw's own peacekeeping force, the Armada provost marshals, reacted the quickest, both thwarting a mutiny within their own ranks and discovering the point of origin of this malignant cyber-attack: the Mechanicum Panopticon Tower.

Quickly the provost marshals organised a proper siege of the Panopticon Tower, but against the automated defences set against them they could achieve little. Fortunately, other, more competent troops arrived at the scene: the elite Veletaris of the 905th Solar Auxilia Cohorts, the "Ash Scorpions". This elite formation raised from the Feral Worlders of Lethe successfully penetrated into the Panopticon Tower, clearing the way with Flamer sections, blasting CastellaxBattle-Automata apart with Rapier-tracked laser destroyers before reaching and valiantly charging the barrier of steel that stood between them and the control pulpit.

Only a single Veletarii whose name wasn't even recorded succeeded in reaching the pulpit, sacrificing himself to shut down the blanketing signal that impeded Lord Admiral LaBray from taking control of the dire situation. Through its glorious sacrifice, the 905th Cohort has gained an undying glory that is remembered to this day.

Destruction Imperial Tithe Fleet

An Imperial warship succumbs to traitorous fire.

Finally able to join the Loyalist ships, Grand Admiral LaBray took overall command and promptly ordered the Dictatus-class Battleship Kurga to destroy the Panopticon lest the signal was somehow reactivated. Manoeuvring on its powerful thrusters, the Kurga made for the imposing spire, the ancient ram-battleship first seizing the Panopticon in its massive set of "jaws" before firing its thrusters at full power, ripping the Panopticon from Port Maw's surface.

Soon battle raged in proximity of the Maw as Loyalists and Traitors slowly formed their lines of battle, but on the outskirts of the muster where the reinforcement squadrons from Numinal and Agathon lay, things were far different. The warships and refugee vessels at anchor had suffered distinctively few mutinies and were still shaking off the effects of the Traitor anathema signal. Puzzled, their captains were still trying to figure out what the commotion at Port Maw was about when almost unremarked one of the Cyclothrathine war-arks, the Arithmetic of Violence, powered her engines and began to move.

The huge ship turned her prow towards the Cruiser squadron hailing from the Agathean Domain, all staunch Loyalists. Without preamble, the colossal barrel-shaped war-ark silently broke apart, revealing row upon row of void torpedoes that ignited their plasma drives as one before racing towards the Agatheans. At such close quarters, there was nothing the brave crews and officers of Agathon could do. The torpedoes obliterated everything in their path, destroying smaller ships and Battlecruisers by the dozens -- leaving only the hence-famous Telemachus to fend for herself and start the arduous journey back home.

With the squadrons from Numinal and Agathon destroyed, the flank was firmly secured for the Traitors, but the overall battle had reached a deadlock. Those ships that could still readily move had gathered into two battlelines facing each other. Neither had such numerical superiority so as to venture forth and force an engagement, both lines keeping out of range of each other and trying to keep Port Maw's mass and the hundreds of floating wrecks between them. It was then that an anomaly appeared on the Triumph of Reason’s radar screens: a faint echo return of an unknown fleet heading for the Maw, answering no hails and broadcasting no security codes.

The echo returns were scrambled, somehow impeded by unknown means that were, however, known to be quite distinctive of Raven Guard vessels in stealth mode. Could it be that some survivors of the XIX Legion had come to Port Maw in its hour of need to help the beleaguered Loyalists? Unsure as to what position he should adopt, Grand Admiral LaBray proved cautious -- he correctly judged the twenty vessels now arcing for Port Maw to be hostile and decided not to let them reach the Traitor lines for it would tip the balance of power in favour of the Traitors.

If, however, they proved to be loyal, they could join with his own fleet before launching a coordinated attack. Bound on an intercept course, the Grand Admiral realised too late that he had been led into a trap. The foremost vessels had indeed once been vessels of the Raven Guard, two modified Dagon-class Grand Cruisers, but behind them came the Vengeful Spirit, flagship of the Sons of Horus fleet carrying Horus himself onto the battlefield.

The Vengeful Spirit

The Vengeful Spirit, infamous flagship of the Sons of Horus Legion.

Using the former Raven Guard vessels as ablative shields to soak up incoming fire, the Vengeful Spirit closed in on its powerful engines. Behind her were arrayed other Sons of Horus ships, forming a speartip whose point was the colossal Vengeful Spirit. Since their time as the Luna Wolves, the Sons of Horus had always valued the precision and utterly devastating effects of the decapitation strike -- a tactic they also adhered to in void battles. It was therefore no surprise that the Vengeful Spirit made directly for the Triumph of Reason at the heart of the Loyalist fleet.

Smashing cleanly through escorting Cruiser squadrons, the Vengeful Spirit launched a perilous manoeuvre that brought her directly above and alongside the flagship -- a manoeuvre no ship its size had any right to survive -- whilst the Triumph of Reason vainly attempted to roll and bring her broadside to bear. Almost at point-blank range the Vengeful Spirit released preciously rare tools of destruction -- Vortex missiles -- that ripped apart both the Triumph’s Void Shields and outer hull before Dreadclaw and Kharbydis Drop Pods delivered Sons of Horus Breacher and Reaver Squads that fought their way through the bowels of the ship with consummate savagery.

LaBray's own elite Lifeguard Cohort resisted where it could, concentrating around corridors and choke-points, their incoming fire potent enough to make even the vaunted Justaerin Terminators stop in their tracks, their Cataphractii Armour turning red and their casements running like hot wax. Casualties were horrifyingly high on both sides, but still the Sons of Horus pressed forward. On the Grand Admiral's order, mechanisms were thrown open and cryo-chambers vented, releasing hundreds of surgically augmented Ogryn Charonites into the corridors of the gargantuan ship.

Hemmed by the narrowness of the Triumph of Reason’s corridors, even the feared Astartes could not stand against these raging, foaming and bellowing monstrosities, their chemically and mechanically-augmented strength capable of ripping through bulkheads and Power Armour alike. The charge of the Charonites successfully disrupted the Sons of Horus' advance, each Charonite wreaking a heavy toll in blood before being finally brought down.

For a moment the battle hung in balance, then the veil between realities parted and the Warmaster himself, Horus Lupercal, stood on the Triumph’s deck. Hefting Worldbreaker, his immense Power Maul, the Primarch led the counterattack, and against him even the chemically-induced fury of the Charonites could not stand. They did not back away, oblivious to the threat the Primarch presented, but were unmade by the Arch-Traitor's strength, their corpses flying apart or crumbling against adamantium walls.

Realising all was lost, Grand Admiral Ospeus LaBray tried to escape from his bridge, making for the fighter bays of his immense flagship, but he perished in a devastating crossfire before reaching them. Whilst the Sons of Horus were set loose to massacre and defile as it pleased them, Horus broke into the Strategium of the Triumph of Reason and there addressed the Loyalist fleet: surrender now and enter his service as penitence for their ignorance and their lives would be spared, resist and only death would come for them.

Thus began Horus' cruel reign of terror.

Under the Lash

Leaderless and hard-pressed, the Loyalist fleet broke apart. Many were the vessels that surrendered, cutting their engines and shutting down their targeting arrays, willfully submitting to the Warmaster's mercy. Others did not heed the words of the Arch-Traitor and valiantly fought on, now vastly overwhelmed but defiant to their last breath. Only a few would try to escape the star system and continue the fight, the Kurga amongst them, as was the Telemachus, the sole survivor of the Agathean Cruiser squadron.

The blood-bedecked Triumph of Reason, most of its crew slaughtered, would now become the base of operation for Horus' chosen regent, a Sons of Horus line captain known by the name of Taloc Thorne. In orbit above Port Maw, its high-performing communication and transmission systems now needing a replacement for the loss of the Mechanicum's Panopticon, the Triumph of Reason would be shed of its name to become The Lash, the seat of governance of the Tyrant of Port Maw, Taloc Thorne.

Horus did not stay long, departing soon after to receive the capitulation of the Manachean Commonwealth following the destruction of Hive Illum. Taloc Thorne would reign with customary violence over his new domain, using the troops allotted to him -- one company of Sons of Horus Astartes and six Cohorts of Cthonian Jackals -- Solar Auxilia recruited from the Sons of Horus' homeworld of Cthonia that were judged too old or unsuitable for Legiones Astartes conversion (but superior to average troops) -- were installed as Port Maw's garrison. Beneath his shadow, the hives of Manachea became little more than vast slave-camps run by those natives who had pledged themselves wholly to Horus and who now competed with each other to prove their loyalty by enforcing the brutal quotas demanded by their distant and merciless overlord.

Quickly operating again thanks to the expertise of the Cyclothrathine Dark Mechanicum, Port Maw would now toil for the Warmaster's benefit. His fleet reinforced by those who had willingly allied themselves to him or had been culled into submission after the Treachery at Port Maw would, however, soon depart the system, fighting on new fronts in Horus' long march to Terra.

The installations and supplies located at Port Maw soon turned the planetoid into a lynchpin of the Traitors' war-effort, the centre of a huge war machine gearing up for the conquest of the Imperium. Nearly every warfleet bearing the Arch-Traitor's banner would come to Port Maw to be refitted, supplied and repaired, gorging themselves on the resources originally intended to supply the vast fleets of the Great Crusade.

While still nominally the seat of power within the Coronid Deeps, Port Maw's influence was severely limited due to its lack of ships. While Port Maw itself and the Manachean Commonwealth remained firmly in control of the Traitors, this lack of mobility meant that the Cyclops Cluster and the Grail Abyss were largely left unguarded, becoming the target of ever more frequent Loyalist raids such as the famous Gethsamaine Raid conducted by splinter-elements of the Iron Hands Legion commanded by the grim Autek Mor.

Left largely unchecked, Traitor-allied factions such as the Knight House Ærthegn and the Mechanicum of Forge World Cyclothrathe openly pursued their own agendas rather than following the orders of Thorne, who had to deploy even more of his finite resources to try to hunt down isolated Loyalist ships and the need to blockade those Loyalist star systems that had proven too powerful to conquer outright such as the Forge World of Mezoa.

Eventually, in the years after the Horus Heresy during the Great Scouring, Port Maw was reclaimed for the Imperium as the surviving forces of the Traitors fled into the Eye of Terror.

At Present

As part of the Imperium's defence measures around the Eye of Terror, apart from other means such as the creation of the Cadian Gate and the raising of the twenty Chapters of the Astartes Praeses, it was decided by the High Lords of Terra to considerably reinforce the sector and sub-sector fleets near to the Eye of Terror.

As such, several of the nearest sub-sectors would harbour their own considerable warfleets to guard the Imperium's borders against those survivors of the Traitor Legions who had fled into the Eye after the Heresy. Although not directly under threat, Port Maw would play an important role in the defence of the Cadian Gate as the new seat and sector headquarters of the Battlefleet Gothic.

Its works completed after several millennia of nearly constant toil, Port Maw was by now a fortress, its growing strategic importance having led to the annexation of the nearby world of Aestellica whose name is now all but forgotten. The entire sub-sector which consisted of the better part of the older Manachean Commonwealth now bore the name of Port Maw, a further testament, if such is needed, to the base's importance inside the Gothic Sector and even the wider Segmentum Obscurus. With Segmentum Headquarters established on Cypra Mundi, this placed Port Maw in second position of overall command within the Segmentum Obscurus.

As the Imperial Navy chronically lacks the manpower to crew all of the vessels at its disposal, Port Maw also became the location where much of Battlefleet Gothic's reserves would be maintained until being called upon. This was further facilitated by the protection offered by Port Maw itself and the ever-expanding defences that now protected the naval base.

Its position uncontested, Port Maw still remains the largest fortress and muster point of the entire Gothic Sector and has participated in almost every major conflict during the last ten millennia. On several occasions it has come under direct attack, most recently during the Gothic War and the 13th Black Crusade of Abaddon the Despoiler. Even though beleaguered and sometimes blockaded as by the famous Conqueror, once the flagship of the World Eaters Legion, during the Gothic War, Port Maw has never again fallen to the enemy since the dire days of the Horus Heresy.

Notable Vessels of the Port Maw Armada

  • Triumph of Reason (Unique Battleship, Unknown Class) - The Triumph of Reason was a vessel with a long and twisted history. Built from the wrecked hulls of two prior Legatus-class Battleships that had been mauled early on during the Great Crusade, the Triumph of Reason was easily the biggest voidship in the entire Segmentum Obscurus Armada. Rebuilt using a unique pattern, the Triumph of Reason was designed from the start to become the flagship of the entire Segmentum Armada and much weight and space was given over to communication and Auspex devices. Stationed at Port Maw for the greater part of its career, placed under the command of Grand Admiral Ospeus LaBray for most of its early years, the Triumph of Reason was equipped with countless cryo-chambers to harbour Ogryn Charonites, the only troops at the admiral's disposal that would prove superior to traitorous Legiones Astartes in case of boarding actions. The Triumph of Reason would participate in the early hours of the Horus Heresy at the notable Treachery at Port Maw Incident where it would assume control and command of the entire Port Maw Armada and its allies once the destruction of the Mechanicum Panopticon at the heart of the treachery had been confirmed. It would be from the bridge of the Triumph that Grand Admiral LaBray would coordinate the battle against the Sons of Horus' fleet, even engaging the lauded Vengeful Spirit of the Warmaster Horus himself. Outmanoeuvred by the Vengeful Spirit, the Triumph of Reason came under attack by Sons of Horus boarding parties and even the Archtraitor Horus Lupercal himself after the first assault wave had been nearly thrown back by the hundreds of Charonites held in the Triumph’s depths. Seized from within and with LaBray slain in his failed attempt to abandon ship, the Triumph of Reason would remain at Port Maw for the remaining years of the civil war, its communication hub needed to replace the destroyed Panopticon. The once-proud Imperial vessel became a glorified, if macabre, throne room for Horus' chosen regent, a Sons of Horus line captain by the name of Taloc Thorne, who renamed the battleship The Lash and took the title of Tyrant of Port Maw.
  • Kurga (Dictatus-class Battleship) - The Dictatus-class was an ancient class of ram-battleship that had slowly become obsolete as the Great Crusade wore on. The Dictatus-class was almost primitively barbaric in its design as its main role was to ram enemy ships and shred their hulls like an ancient seaborne predator with its enormous jaws -- a tactic that seems more suitable for the dreaded Orks than the Emperor's servants. Mounted on a set of hydraulic platforms these "jaws" comprised a row of nearly thirty-metre-long teeth-spikes, while its "mouth" supported scores of rocket-powered Melta-barbed harpoons not unlike the more massive Ursus Claw that was the pride of the World Eaters flagship, the Conqueror. The Kurga was present at the Treachery of Port Maw from which it remained one of the few Loyalist ships that succeeded in making good its escape, despite having to crush a mutiny on board. It remains famous to this day for having ripped the Mechanicum Panopticon tower away from the surface of Port Maw which Traitor elements had used to sabotage the Armada's communication network and targeting arrays. The Kurga would go on to fight with distinction in the years after the Treachery, its powerful drives and unorthodox tactics proving a valuable asset in the dark years to come.


  • The Horus Heresy - Book Four: Conquest (Forge World Series) by Alan Bligh, pp. 10-11, 36-54, 72-73, 86-89, 189
  • The Horus Heresy - Book Six: Retribution (Forge World Series) by Alan Bligh, pp.38-39
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