Mezoa - History: Mezoa is a vast, highly volcanic world which was naturally incapable of sustaining life but immensely rich in metallic elements. It was first colonised sometime in the Age of Strife by one of the three Explorator Arks sent out by the Forge World of Lucius after its quarrel with Mars, or according to other sources, to comply with an Edict Imperialis of the Emperor of Mankind and establish a further outpost to supply the armies of the Great Crusade.What is known is that the orthodox Lucien Mechanicum used this opportunity to rid themselves of an aberrant sect growing in their midst whose schismatic ways would eventually give birth to the Cult of the Flame Eternal, which still dominates on Mezoa to this day. Thus, the Forge started as an isolated outpost of the Lucien Mechanicum and wasn't rediscovered during the Great Crusade until 540.M30. By then it had already expanded to something resembling a Forge World, a pocket-empire in the wilderness of space.Mezoa itself was ringed with concentric layers of orbital docking platforms and habitation modules, the ash and cinder-wreathed surface of basalt having proven too unstable to support the original forge-fane's expansions. Beyond these rings lay outer boundaries of autonomous planetary defence batteries, kill-satellites and spatial mine-fields guarding the world's approaches. These formidable protections were far greater than those possessed by other individual Forge Worlds, yet they had not been constructed out of simple caution or paranoia, but had been tested on many occasions, particularly during the decades-long xenocide campaigns against the Mitu Conglomerate -- the Warp-capable alien pocket-empire which controlled much of the region of the Coronid Deeps before the coming of the Imperium.Being besieged and bombarded on numerous occasions by the foul xenos before their eventual eradication by the forces of the Great Crusade, the Mechanicum of Mezoa had grown into one of the most militant and military-minded acolytes of the Machine God. This military prowess and battle-readiness vastly accelerated Mezoa's recognition as a fully-fledged Forge World, a status it obtained officially in 813.M30 under pressure of an Imperial Edict, for the Emperor of Mankind had wished for the Martian Mechanicum to establish a new outpost in the Cyclops Cluster to further consolidate Imperial power in that region of space.Loathing to expend its might on a colony of one of its fiercest rivals, Mars delegated the task to reinforce and expand the colony of Mezoa to the authorities of Lucius. The Mezoan Forges were rebuilt under the direction not only of the Archimandrites of the Cult Mechanicus, but also the minds of both the Emperor and, it was said, the Primarch Ferrus Manus in later years after joining the Imperium. Great spindle-spires of metal rose out of the planet's surface, jutting like ziggurats, kilometres in height, from magma flows, and vast naturally-occurring lakes of molten iron dotted its landscape. Forge-fanes encircled the planet like a garland of barbwire.This new Forge World was almost solely dedicated to the production of heavy arms and armour, its production ranging from Battle Cannon to warship hull plates; a fane of weapons and armaments solely intended to serve the needs of the ever-advancing front lines of the Great Crusade. Over the centuries leading to the Horus Heresy, the cult's dogma would be heavily influenced by the quixotic beliefs of the Hierarchs of House Hermetika -- who quickly became the Forge World's closest allies -- and would eventually give birth to the creed known as the Path of the Eternal Flame.As militarily powerful as Mezoa had evolved to become during the years of the Great Crusade, one noteworthy idiosyncrasy of the Forge World was that it did not possess a sentinel Titan Legion, either of its own or as an ally. This was simply a consequence of the world's fluctuating and perilous terrain, which was entirely unsuited to Titan operations, both because of the planet's shifting topography and because where its scorched black surface was solid, such ground was likely to prove no more than a skin of solidified magma, treacherously unable to bear a Titan's weight.Though this geological instability arguably robbed Mezoa of its most powerful potential guardians, it was also itself a final and telling line of defence, as events were later to prove. If the Mezoan forges somehow voluntarily renounced its Titan-production capacities, that was not the case for its Imperial Knight production-lines which worked tirelessly to equip those Imperial Knight Households oath-bound to it.Most notable amongst these allies were the Knights of House Hermetika, which had stood at the side of the Forge World since the dark days of the Age of Strife, and noble House Vyronii. House Makabius nominally owed fealty to the lords of Mezoa, but later chose to side with the Warmaster and subsequently turned Traitor.