A Sacristan is an artificer of the Knight Worlds who is inducted into the Cult Mechanicus, trained during a decade-long apprenticeship upon the Forge Worlds of the Adeptus Mechanicus in the skills needed to maintain and repair the suits of Imperial Knights, and then returned to their planet of origin. The Imperial Knights, however, do not realise that their Sacristans are also full members of the Cult Mechanicus, and provide a network of agents who can further the interests of the Tech-priests of Mars on the Knight Worlds. The Sacristans hold much political power on many Knight Worlds despite their legally subservient position as vassals of the nobles of the Knight Houses, for their knowledge is crucial to keeping the nobles and their Knights ready for battle.
Far back in Mankind's history, during the dawn of the Age of Technology, humanity forged out into the stars with hope and trepidation in their hearts, seeking to extend their dominion over the vast and mysterious gulfs of space. Sublight Long March colony ships soared out from the human homeworld, tiny motes of life drifting through the vast tracts of unexplored space. When the Long March colonists settled their assigned worlds, upon making planetfall they quickly discovered that many of these worlds were often inhabited, either by monstrous predatory beasts or sentient alien races that resented the sudden appearance of these invaders from beyond the stars. To protect them against all of these terrible threats, the colonists had their Standard Template Constructs -- miracles of technology whose fragmentary remains are still prized to this day by the Adeptus Mechanicus. Each Standard Template Construct database and fabricator assembly allowed the settlers to mass-produce a specific object or device flawlessly and without the need for skilled engineers. From domestic tools to weapons of war, the STCs were the single most important tool the colonists possessed to ensure their survival. Foremost amongst these devices were those that produced the bipedal exo-suits that came to be known as Knights. The Knight suits proved all but unstoppable, acting as the mailed fist of interstellar human colonisation and carving out new realms within which Mankind might prosper and thrive.
Somewhere between the 22nd and 25th Millennia, the beginning of the time of interstellar darkness known as the Age of Strife closed in with horrifying swiftness upon Mankind's galactic domain. Thinking machines rebelled against their masters, slaughtering whole planetary populations like cattle or plunging them into worldwide wars of mutual annihilation. Monstrous and unnatural phenomena were unleashed that depopulated worlds in mere solar hours. Colonists died screaming amid madness and horror, or else loosed world-killing weapons and horrifying phages to secure their own destruction before a worse fate could consume them. Warp Storms roared into being that cut off worlds or even whole star systems, trapping them in hells of their own making from which none could escape. Amid all this horror, as the darkness engulfed one gleaming monument to human endeavour after another, the Knight Worlds simply endured. Their very conservatism and backward nature had insulated them, ensuring they were sidelined and forgotten by those who might otherwise have brought them to ruin. During this time, their neo-feudal societies became even more insular, the knightly houses consolidating their power bases and defending their borders with grim tenacity. Cut off and forced to fall back on their own means, the Knight Worlds became entirely self-sufficient. During this period of isolation, the technical caste that repaired and maintained their lords' Knight suits first rose to prominence -- though they were still vassals of the Knight Houses. It was widely recognised that without such craftsmen, the armoured battlesuits of the nobles would cease to function, leaving their people defenceless. Indeed, despite the best efforts of the nobles and craftsmen both, many Knight Worlds did fall into decline, or else were overrun by the creatures that crawled from the darkness of Old Night. Yet many more endured, stoic as ever while the standard years became centuries and the centuries millennia.
The Great CrusadeEdit
It was not until the glorious years of the Great Crusade in the late 30th Millennia that contact was reestablished with the surviving Knight Worlds. When the first Rogue Traders discovered one of these scattered enclaves, they quickly recognised the potential in the towering fighting machines and the robust society that supported them. Upon returning their findings to the nascent Imperium of Man, the Rogue Traders strongly recommended that these Knights be returned to the Imperial fold, for their value as a military asset could not be overstated. Further, it was asserted that where one Knight World had survived though the darkness of Old Knight, surely more must have done the same. They should be sought out and returned to the bosom of their race so that they might aid in the furtherance of the Imperial Truth. Not only were the Knight suits incredibly potent weapons of war, but their planets of origin were still rich in resources. Perhaps most important of all, these were worlds still rich with the marvels of the Age of Technology. Though many devices had been forgotten, abandoned or destroyed as the years passed by, still the Knight Worlds were treasure troves of archeotech and mechanical wonders. For this reason, it was the Mechanicum who strove the hardest to seize the Knight Worlds for their own.
As the Great Crusade rolled out across the galaxy, the Mechanicum established hundreds of new Forge Worlds. Many were built amid the ruins of past glories, worlds once rich in the iron bounty of progress. Others were hewn from unsettled worlds found to be well positioned or heavy with natural resources. Yet regardless of the Mechanicum's stated reasons, it seemed that a surprisingly high number of their newly founded centres of power lay close to one or more surviving Knight Worlds. Each time this happy coincidence occurred, the Forge Worlds' senior Magi wasted no time in dispatching missionaries to aid these long-abandoned enclaves of humanity. In return for the ruling nobles' pledge of military aid, the Mechanicum offered the word of the Omnissiah, and the ancient knowledge that came with it. The artisan castes of the Knight Worlds had done what they could to stave off the rigours of time, yet precious few of the nobles' Knight suits still operated at anything close to optimum efficiency, and many had ceased to function at all. By inducting the craftsmen and armourers into the mysteries of the Cult Mechanicus, the Mechanicum could provide the Knight Worlds with the ability to regain their former glory.
While few refused the Tech-priests' gift of knowledge, most did not give themselves over completely to the Omnissiah, instead retaining their own independence and swearing their allegiance to the Emperor instead. As for the Knight Worlds that wholly accepted the aid of the Martian Priesthood and the word of the Omnissiah, their nobles had given away much of their autonomy and freedom. Vows of allegiance now obligated the nobles to lend military aid to the Mechanicum whenever it was demanded. More insidious, however, was the change that had occurred in their artisan classes. The craftsmen who saw to the well-being of the Knight suits endured indoctrination and reeducation at the hands of the Tech-priests. Most submitted willingly to this decade-long process, for the end result would be unsurpassed skill in the trade that they and their forebears had practiced for generations. As the Mechanicum inducted these craftsmen and artisans into their deeper mysteries, so they renamed them Sacristans and indoctrinated them into the Cult Mechanicus. The Sacristans returned to their worlds offering unequivocal service, yet their allegiance was now to the Mechanicum, body and soul.
As the years passed by, the Sacristans established themselves as a religious brotherhood, an order of half-remembered mysteries and veiled secrets. Gradually they began to speak with one voice, soon coming to wield significant political power through the threat of withholding their knowledge and expertise. This did not work on every Knight World, for the Sacristans were still technically the nobles' legal vassals, and on some worlds weight of tradition or force of personality cowed the Sacristans into subservience. However, this was the exception rather than the rule. In general, this has benefited the knightly houses, for the Sacristans act as something of a counterpoint to the natural arrogance and warlike tendencies of the Knights, and have often been able to arbitrate between different houses to ensure they do not wipe one another out in bitter feuds. While other organs of the Imperium had blustered, bribed or bullied in an attempt to win the Knight Worlds to their cause, the Mechanicum had performed a slow and silent invasion that had left the Knight Worlds dependent upon them for their continued existence. Even so, the Mechanicum had not counted upon the fierce independence inherent in the Knight Worlds' nobility. So it was that while many Knight Houses would become beholden to the Mechanicum many more would still choose to stand apart.
- The Iron Brotherhood - One of the secrets behind the strength of Adeptus Mechanicus-aligned House Raven is the large and highly skilled order of Sacristans that oversees the repair and welfare of its legion of Knight suits. Known as the Iron Brotherhood, these Sacristans spend many long years on the Forge World of Metalica learning the way of the machine before they are officially inducted into the order and entrusted with the stewardship of a suit of Knight armour. As a result, the Sacristans of the Iron Brotherhood are amongst the most skilled of their kind in the galaxy, save perhaps those who serve House Taranis on Mars itself.
- Codex: Imperial Knights (6th Edition), pp. 26-27, 31, 43, 52, 70, 72
- The Imperial Knight Companion (6th Edition), pp. 6-7, 9, 68