M'Pandex, also known in ancient sources as Mappandax or Zaphadak, is a Secundus II Grade Forge World of ancient provenance and tumultuous history. Founded during the dark years of the Age of Strife and isolated from the domains of the Mechanicum and humanity for much of its history, the Forge World's fortune waxed and waned until its later rediscovery by the forces of the Great Crusade in the 30th Millennium.
Restored to its former glory by the efforts of the Martian Priesthood, M'Pandex would become an important Forge World for the whole Cyclops Cluster, although being overshadowed by the the might of its rival, the Forge World of Mezoa. Following in the footsteps of Mars, M'Pandex quickly sided with the Warmaster Horus during the Age of Heresy, willfully joining the Dark Mechanicus until its purge during the Great Scouring.
Although overshadowed in most regards by its neighbour Mezoa, M'Pandex is in fact considerably older than its rival, owing its origins to Martian Explorator Arks launched during the Age of Strife. The exact nature of its founding and its early history, however, remain shrouded in the lost anarchy of the past, and it seems the Forge World itself fell out of contact with both the Mechanicum and wider humanity for much of its history.
In the long years of isolation, it is evident that the Forge World went through several cycles of expansion and collapse, each cycle ending in environmental and/or civil calamity and progressively degrading its technological capabilities, the understanding of its Magi and the stability of its population's genome.
Such was M'Pandex's fall that even the command of the Lingua-Technis -- the sacred language of the Machine Cult -- suffered, leading to the widely held supposition that the Forge World's self-given name, sometimes variously rendered "Mappandax" and "Zaphadak" in the local idiom, is in fact the corruption of an older, purer title. In the same manner, M'Pandex possessed few Titans which remained repairable over the centuries and had mostly fallen into ruin, serving as no more than inanimate idols to the Machine Priesthood.
When M'Pandex was rediscovered by chance by the 90th Expeditionary Fleet, it was barely recognisable as a domain of the Mechanicum, ruled by factitious and superstition-bound warlords scarcely able to claim the lineage of Magi, while much of its dwindling population had descended into abhumanity. Regardless of its parlous state, the Lords of Mars would not see a Forge World, however reduced, pass into oblivion, and considerable effort was spent by the Mechanicum rebuilding M'Pandex's infrastructure, re-educating its wayward inhabitants and weeding out the worst of them or driving them deep into the planet's long-petrified jungles.
Much had been irrevocably lost, unfortunately, and it may also be true that the Martian Mechanicum, despite their best efforts, did not entirely trust those of M'Pandex, and garrisoning forces of Skitarii and a demi-maniple of Titans of the Legio Mortis were stationed there not so much as protectors, but as wardens, beholden to Mars, not the High Ourteka M'andii of the Golden Forge.
The planet's reconstructed industries were notably focused not on macro-weaponry, arms or armour, but on the mass production of items of logistical supply and prefabricated materials; just as vital to the Great Crusade, but clearly of less direct use in any potential revolt. Eager to prove its loyalty, the forges and manufactoria of M'Pandex ran ceaselessly to show their worth, and by the time Horus was proclaimed Warmaster, their output rivalled those of even such mighty Forges as Lucius and Vannaheim in volume, yet the Forge World remained in the shadow of its upstart neighbour Mezoa, both in prestige and influence.
The Horus Heresy
M'Pandex's involvement in the unfurling Heresy began in 006.M31, at the height of the spreading alarm throughout the Cyclops Cluster. Both Mezoa and M'Pandex, the two greatest independent powers within the region, each received the Emissary of Mars, a Magos known as Regulus, or at least an entity bearing that name as there are extant contradictions in the record regarding the location of this individual at various times.
This senior Tech-priest of the Mechanicum had for many Terran years served alongside the Warmaster Horus, long before the betrayal at Istvaan, and now remained his, body and soul, being part of Horus' inner circle and bound in allegiance to the Traitor's cause. Regulus came bearing dual patents of authority, the first from his Warmaster and the second from the hand of Kelbor-Hal, none other than the Fabricator-General of Mars, and by right the voice of the Omnissiah and Supreme Pontifex of the Mechanicum.
Kelbor-Hal had also thrown his lot in with the Traitor Horus, sparking a civil war on Mars itself, a fact not yet known by those in the Cyclops Cluster. Regulus made an offer and a demand; the demand was for fealty, that the Magi of M'Pandex serve the Warmaster as their own Fabricator-General bid them to do. That they obey him and offer up their arts and the fruits of their forges for him and his armies, and open their ports to his warships, while denying these things to both the forces of distant Terra and the local Imperial Commanders, already demonstrably squabbling amongst themselves in fear and disunity.
To honey the threat of force, Regulus offered the Warmaster's protection for their Forge World and, just as he did to sway Kelbor-Hal to his cause, he offered gifts: STC technologies harvested from the later Great Crusade era and kept solely by Horus and those he trusted, and the freedom to pursue those technologies and arcana the Emperor had so cruelly and ignorantly denied them as forbidden knowledge since the Treaty of Mars.
On M'Pandex, Regulus was greeted with great reverence and courtesy, and personally led to direct audience with the High Ourteka of M'Pandex to plead his case. What passed between them at this private conference is unknown, but from then onward and without recourse to consorting with the synod of M'Pandex Magi for confirmation, the Forge World was pledged to the Warmaster. There was in some quarters brief but violent resistance to this new order, but the world was long-used to internecine conflict in its ranks, and the High Ourteka was merciless in wielding the handful of Martian Skitarii and the small detachment of Legio Mortis Titans based there to aid in his world's protection, now his private enforcers, to ensure compliance.
This new allegiance, while firm, was not widely broadcast and was unknown to outsiders. M'Pandex was quickly girded for war, its production capacity ramped ever higher and now destined for Horus' armies, while whatever Loyalist or merchant voidships passed into its space were seized and impounded, their crews and complement forcibly converted into adsecularis slaves for a growing Taghmata of the Forge World's own. M'Pandex's military and especially its naval might was quickly put to good use, reinforcing the blockade of its long-time rival Mezoa and seizing its vassal worlds for precious resources which quickly fuelled M'Pandex's war effort.
- Codex: Adeptus Mechanicus (8th Edition), "Bastions of the Machine God," pg. 12
- Imperial Armour Volume One - Imperial Guard & Imperial Navy, pg. 8
- The Horus Heresy - Book Four: Conquest (Forge World Series) by Alan Bligh, pp. 24-27, 30, 35, 54, 67-68, 236-237