Incaladion is an Imperial Forge World of the Adeptus Mechanicus that is located in the Segmentum Ultima of the Milky Way Galaxy. This world was once home to the sinister and ill-reputed Legio Fureans ("Tiger-Eyes") Titan Legion. Following the end of the Horus Heresy, when the Traitor Legions were driven into the hellish realms of the Eye of Terror, the newly reformed Adeptus Mechanicus deemed that Incaladion's worth as a Forge World and its potential industrial output was worth saving. Since that bygone era, Incaladion has continued to serve as a vital Forge World of the Imperium, though recently Incaladion was incriminated in a conspiracy connected to techno-heretics and worship of proscribed xenos-lores. It is known that Incaladion is a Production Grade III-Prima Forge World with a Tithe Grade of Aptus Non, meaning it pays no tithe to the Administratum, as its industrial output is considered of potent strategic value for the Imperium in and of itself.
The Forge World of Incaladion was a world caught in an unceasing cycle of war, strife and invasion that had wracked it before it was liberated by the forces of the Great Crusade. Founded by the a Mechanicum Sleeper-Ark during the Age of Strife on a world rich with an abundance of rare mineral resources as well as the necessary organic compounds for sustaining a biosphere, Incaladion ought to have offered a perfect locale to found a Forge World, but the same stable Warp-currents that had succeeded in carrying the Mechanicum to the world were, as time progressed, to bring a host of less-welcome voyagers. Records of its founding centuries remain fragmentary, but it seems certain that alongside the vast works of macro-construction and geo-forming the Mechanicum colonists undertook, conflict and battle were nearly constant against a host of invaders. As a result, the Incaladion Mechanicum, separated by vast distance from Mars, evolved into a distinctive and highly warlike faction, and one that was seldom united as individual forge-fanes often had to look to their own defence and survival unaided. Waves of xenos invasion spurred unusual avenues of technological development and the creation of vast fortified cities which dominated and defended the richest mineral seams and algae-rich seas, while hidden forge-fanes were sunk kilometres beneath the planet's crust. The Incaladine also adapted to the need to acquire additional human stock by raiding the feral populations of the world, which brought echoes of barbarous and macabre cultures that began to infect the increasingly schismatic Machine Cult propagated by the Incaladine Mechanicum.
Throughout this long and savage history, the Legio Fureans formed the principal military force of Incaladion's ruling Archmagos, known as the Preceptor-General. Its Titans served as the avatar of her will. No resource was spared in the Titan Legion's maintenance, and where possible due to lulls in the fighting, the expansion of its fighting strength. Their more common cognomen the "Tiger Eyes" also stemmed from this early period as a corruption of the name given to them by the feral tribes of the nearby world of Humardu, to whom the Titans truly were divine and terrible beings come to reap a sacrifice of the young and the strong to serve in the palace of the gods. Unlike some garrisoning Titan Legions before the Great Crusade, the Legio Fureans did not stand vigil as enforcers for petty empires of the Machine God's servants, but rather fought an unceasing war against a host of foes. For centuries the Legio Fureans unleashed their wrath against invading hordes of Ork marauders and the spiteful raids of Yldari corsairs, scavenging Tarellian war-packs and the colossal viscid horrors of meteor-brought Carnoplasm infestations from the Abyssal Reefs. Such ceaseless conflicts took their toll, however, both on Incaladion itself and the Legio Fureans who defended it.
Around fifty standard years before the Great Crusade would finally reach Incaladion, after a particularly brutal series of incursions and raids, the Taghmata Omnissium -- the feudal order upon which the defence and military hierarchy of a Forge World of the Mechanicum is based -- finally broke down. In the ensuing strife, the Preceptor-General of Incaladion was assassinated and the Forge World split into warring or isolationist factions, bereft of central control or co-ordination, laying it open to invasion and the devastation which followed. By the time the Great Crusade's advance elements reached Incaladion, it was a global battleground, disported by a dozen different armies; Mechanicum, Renegade and xenos unleashing atomic fire and yet more savage weapons upon each other. During this time, overwhelmed and vastly outnumbered, the Tiger Eyes refused to retreat or retrench, and shattered its blade on foes uncounted until it became only a shadow of its former might, reduced to defending the last forge-fane of its dead regent.
After Imperial contact, Mars was determined to bring Incaladion into the fold of the Imperium, but the Great Crusade was as that time engaged in major battles on a myriad of fronts and much of the Mechanicum's military forces were tied up in on-going campaigns. It instead fell to the 8th Expeditionary Fleet's frontline forces of the IV Legion (not then yet having taken the name of the Iron Warriors) to bear the brunt of the liberation campaign, with such supporting elements of the Legio Mortis and Martian Skitarii and Secutarii forces as could be spared to aid it. The resulting campaign (which lasted from 842-843.M30) was to prove the bloodiest in the IV Legion's history to that point, but after two solar years of guerrilla warfare, Incaladion joined the Imperium. In the aftermath, the lost forges and fortress-citadels were quickly reclaimed and repaired by the now ruling Imperium-backed Mechanicum faction. Warship squadrons, now permanently based in the Incaladion System, gave the Forge World respite from attack for the first time and the vast mineral wealth and production capacity of the planet was quickly put into action to fuel the ever-expanding Great Crusade. Oaths of loyalty and debts of blood to the liberators were affirmed, although in this Mars and the Legio Mortis were judged by the Incaladine Mechanicum to be their saviours, rather than the IV Legion who had expended so many lives in the war. As a key part of repaying this debt, the Legio Fureans was quickly reconstituted and rearmed, with the deep Titan-forges beneath the planet's surface put to continuous operations to fuel a second birth for the Titan Legion. Travelling beyond Incaladion, the Legio Fureans pursued conflict with an aggressive fervour and tempo of battle seldom matched by any other Titan Legion of the period, splitting their forces into demi-legios and strike groups operating alongside numerous Imperial Expeditionary Fleets and extermination forces.
When the wars of the Horus Heresy broke out, it was revealed immediately that the Legio Fureans had sided with the Warmaster, as did both the Fabricator-General of Mars and the Legio Mortis. It is clear in hindsight in fact that the Legio knew of the planned treachery beforehand and were a key and willing part of the Warmaster's early battle plans and deployments from the start, such as the dispatch of a demi-legio of the Tiger Eyes to the Paramar assault force before blood had yet been spilt on Istvaan V. Quickly too would the darker rites of the Legio blossom into the twisted arcana of what would become known as the Dark Mechanicum in later years. Incaladion conversely, through declaring for the Traitors' cause fell quickly into a bloody civil war of its own, the absence of the Legio having stripped its new Preceptor-General's principal agency of overmatching power against his rivals.
- Imperial Armour Volume One - Imperial Guard & Imperial Navy, pg. 8
- The Horus Heresy - Book Three: Extermination, pp. 87, 106-107, 154-157