Mezoan Campaign



The Mezoan Campaign, sometimes also referred to as the Third Siege of Mezoa, was a great battle fought in the opening years of the Horus Heresy. It marked the last concentrated effort of the Traitor Warmaster Horus Lupercal's forces to seize control of the strategically important Mechanicum Forge World of Mezoa, the last star system still loyal to the Throne of Terra in the Gothic Sector. Besieged by elements of both the Alpha Legion and Iron Warriors, Mezoa was only saved through the timely intervention of the Disciples of the Flames, a splinter-faction of the Salamanders Legion. The Third Siege of Mezoa is a visceral lesson in the remaining effectiveness of the Shattered Legions, those Legiones Astartes broken or annihilated at the Drop Site Massacre who were still able to intervene and hinder the Warmaster's carefully-laid plans. While few at the time saw little significance in the Loyalist victory, the actions of the Shattered Legions proved successful in slowing Horus' march towards Terra. The Mezoan Campaign also provides one of the few reliable accounts of the actions of Blackshield forces during the conflict.

War in the Coronid Deeps
Following the revelation of the Warmaster's true intent in the Istvaan System, the worlds of the Coronid Deeps were the first to suffer from the Traitors' expansive efforts. Led by the Warmaster himself, the Sons of Horus quickly captured the heavily industrialised Manachean Commonwealth in the short-lived Manachean War, whilst their allies in the Death Guard under the command of their own Primarch Mortarion cleansed the strategically less important Grail Abyss of all life. Most importantly, through the events of the Treachery at Port Maw, the Warmaster captured a sizable naval fortress and orbital shipyard which would allow him to rearm and repair his fleets on the long march to Terra. By the end of 008.M31 only a few Imperial domains were spared the wrath of the Traitors' armies. To the galactic west, the isolated worlds of the Agathean Domain were deemed too insignificant to squander valuable military resources on conquering it, while in the Cyclops Cluster the Forge World of Mezoa proved a far too difficult target to assail readily. As the Great Crusade had done centuries before, the Traitors' advance would circumvent Mezoa and blockade it until enough men and resources could be gathered to take the strategically important domain of the Mechanicum.

While many worlds of these far-flung territories were deemed not valuable enough to offer any kind of coordinated resistance or threat -- which at least in the case of the Agathean Domain would prove to be a gross miscalculation -- the Warmaster knew that he could not ignore the powerful Mezoan Mechanicum. However, having challenged his father for the rule of the entire Imperium of Mankind, Horus, the pretender, could not afford to be delayed in the Coronid Deeps, but had to be seen on the frontlines, leading new conquests and rallying new star systems to his banner. The task of eliminating the threat posed by the Loyalist Forge World would be handed down to other military commanders belonging to the Warmaster's allies. Yet such a general could not readily be found. Horus' own puppet-ruler, Taloc Thorne, the Tyrant of Port Maw, lacked the military forces to both maintain productivity in the Manachean Commonwealth and conduct a military campaign of the scale required to conquer the belligerent Forge World. Horus' principal ally in the region, the Dark Mechanicum Forge World of Cyclothrathe, preferred to accomplish its own objectives rather than obey Thorne's orders. In truth, only the Forge World of M'Pandex, a long-time rival of Mezoa, showed any devotion to the Loyalists' eradication. But long eclipsed by its rival, M'Pandex too lacked the military resources to vanquish Mezoa alone. Two previous attempts to seize Mezoa's principal forge-fane had already been repelled, the Mezoan Magi using their world's own volcanic might against the invaders, letting the ground collapse under the Traitor's landing zones and rerouting lava-streams to stall any advance or burn their enemies to ashes. Some of the most exotic reports of the earlier campaigns from the survivors even told of kilometer-long chunks of solidified magma, essentially man-made asteroids, that had been flung as projectiles at incoming enemy ships. The kinetic impact alone had been powerful enough to break a voidship in two.

The Poisoned Chalice
Even as the wars of the Horus Heresy unfolded, the defiant Forge World still resisted every attempt at conquest by the Traitors. Words of Mezoa's continued defiance did not fail to reach Horus, and it is said that his wrath was terrifying to behold. Those records captured by the servants of the Emperor in the wake of the Warmaster's defeat attest of a vast armada gathering at Port Maw, where the fleets of those Legions loyal to Horus were refitted and repaired with the materials once intended to ensure the progress of the Great Crusade. It was here that Horus' latest proclamation was presented to his generals -- a formal order to destroy Mezoa. This order was so widely promulgated that several illuminated copies of this manuscript have survived to this day and are actually preserved in both the Imperial Archives of Terra and the Inquisitorial Archives on Tethys.

The elimination of the threat posed by the Loyalist Forge World was a necessity. With his armies mustering for their final push towards the Segmentum Solar, the Warmaster could not allow any potential weakness in his rear, or risk exposing the Traitors' vulnerable supply lines. But however important the conquest of Mezoa, every Traitor commander present at Port Maw knew that victory would only be achieved at a tremendous cost in lives and materiel. As a result of Mezoa's tectonic instability, the powerful God-engines of the Collegia Titanica could not be deployed, dramatically increasing the cost of taking the defiant Forge World. With much glory to be won in the oncoming wars, Horus' commanders were loath to weaken their forces at such an early juncture. Yet, none were so foolish as to openly refuse or ignore the will of the Warmaster.

Knowing that Horus' eyes rested upon them, a silent war of influence erupted between the commanders of the Traitor forces. Through veiled threats, outright lies and no few fatal confrontations, the officers of the Archtraitor's armies each sought to see the mission assigned to one of their rivals. For solar weeks this silent war went on, until the proverbial scapegoats presented themselves at Port Maw. Humbled by their defeat at the hands of the Shattered Legions during the Siege of Epsilon-Stranivar IX -- colloquially known as "Fortress Stranivar" -- the 78th Chapter of the Alpha Legion under their Consul-Delegatus Autilon Skorr and the depleted 114th Grand Battalion of the Iron Warriors arrived at Port Maw. In the absence of their respective Primarchs, both formations lacked influential patronage or an unified officer cadre that would have been able to oppose the alliance of previously established commanders. So it came to pass that these forces would have to take up the poisoned chalice and prosecute the Mezoan Campaign to its conclusion. In recognition of his rank, Autilon Skor was appointed as overall commander of the new taskforce and given access to Port Maw's vast stockpiles of arms and materiel.

Even in the wake of his defeat on Stranivar, Autilon Skorr's ambition was undimmed. Being fully aware of the enmity borne for him by most of the command elements of the 114th Grand Battalion, Consul-Delegatus Skorr used his new position as commanding officer of the Mezoan taskforce to appropriate the lion's share of the available resources for his own 78th Chapter, leaving the Iron Warriors elements under Nârik Dreygur little chance to recover from their previous losses. With the bulk of the IV Legion and their volatile lord, the Primarch Perturabo, deployed far away, Dreygur's pleas for help or materiel fell on deaf ears, the other commanders seeing little interest or profit in aiding one they regarded as a failed officer. With no other choice left to them, Dreygur and his Iron Warriors had to make what repairs they could and tend to their wounds, their resentment against Skorr growing even deeper.

Composed of a dozen capital class warships -- including a pair of the fearsome Mangonel-class Bombardment Cruisers, 9,000 Legiones Astartes, three full Taghmata from the Renegade Forge World of M'Pandex and 20,000 auxiliary troops, the Mezoa task force was one of the largest battlegroups assigned to an independent command that was not under the control of a Primarch. Knowing that victory in this particular theatre of war would ensure gaining the favours of the Warmaster, an invaluable commodity once Horus sat upon the Golden Throne, Autilon Skorr began his preparations. Departing in good order, the fleet entered the Warp, the Davinite Lodge Priests attached to the fleet's Navigator-contingent assuring Skorr that their passage would be swift and sure and cleared of all storms. In a few short solar days, the fleet entered the Mezoa System, but they soon discovered that they were not the first to arrive...

Devils from the Outer Dark
"All things must be tested upon the anvil and beaten until the heart of their being is exposed and measures. This is true of loyalty as it is of steel, for loyalty that is never tested is worthless as flawed metal."

- Codicil 13:9 of the Book of Vulkan

As one of the few bastions of Imperial resistance,the Forge World of Mezoa had been reinforced by splinter forces of the Shattered Legions and even Loyalist survivors of the Armada Imperialis which had been present at the Treachery at Port Maw. While welcome, these reinforcements failed to considerably alter the balance of strength. The mighty Forge World, a glowing ember encircled by a dense ring of orbital defence stations and kill-satellites could not hope to match the Traitors' numbers. Even worse, Autilon Skorr had learned his lessons from the fiasco at the Siege of Epsilon-Stranivar IX and ensured that all his ship's captains would obey his world, while the Loyalists' command - even though united by a common goal - was fractured. Neverless, the rag-tag Loyalist fleet which bore countless differents icons bravely opposed Skorr's attempts to gain local space superiority. Soon, a chaotic void battle developped where the vessels of the Iron Warriors and Alpha Legion - numbering more heavy Cruisers - started to gain the ascendency. It was then that unheralded a new force emerged from the Warp at the very edge of the Mezoan System. Unsure as for which side the newly arrived ship would declare, the battle ebbed, no new explosions illuminating the void as both sides turned their powerful augur banks toward the unidentified ship that had emerged behind the Traitors' battleline. ''