Ordo Reductor - The Covenants of War: The individual commands of Ordo Reductor Magi and their attendant servants and war machines, known commonly as "Covenants", were based almost entirely on purpose-configured warships. These were often long-range, self-sustaining Galleass types birthed in the vast shipyards of Saturn for this express task, rather than the more common Arks-Mechanicum. It was these voidships which served as transport, fane and permanent base for the Ordo Reductor in the days of the Great Crusade and were their only sovereign domains, but domains they guarded jealously, even from their brother Mechanicum. The very treaty that had created them had also split the Ordo Reductor from the Forge Worlds and the bulk of the Mechanicum in a very real sense, and set them in thrall on the front lines of the Great Crusade from where they would seldom stray. The "Brazen Vultures" of the Ordo Reductor, as the void captains of the Imperialis Armada came to call their ships, passed as baleful mendicants and nomads from war zone to war zone as the ebb and flow of the fighting -- or the will of some Primarch or other great lord of the burgeoning Imperium -- dictated.Because of their relatively small number, wide physical dispersal and their calling as war-savants, more often than not Ordo Reductor Covenants served the various Expeditionary Fleets and theatre commands in the roles of battlefield intelligence gatherers, warrior-seers and savants of carnage rather than as conquerors in their own right -- the Space Marine Legions more often than not putting into practise what an Ordo Reductor Magos' blood-drenched wisdom had learned to deadly effect. The Reductor's own forces were seldom seen to act directly in battle save to conduct targetted raids and probing strikes ahead of a main advance, or to haunt still-burning battlefields making a tally of the dead and the destroyed to further their studies. This disposition held true in most cases except one; that of siegecraft. This sphere of warfare with all of its lethal complexities and unforgiving logic was to the Magi of the Ordo Reductor a thing of sublime and dark mystery, and in its discipline they found purity and in its merciless execution they found the echo of the divine Omnissiah. In the arts of the siege, the Magi of the Ordo Reductor acknowledged no superior and few equals in their cold pride, save a handful of the Primarchs of the Legiones Astartes. This presumption was not without its justification, as in countless sieges and assaults, the Covenants of the Ordo Reductor proved able to sunder defences thought unconquerable and survive Zone Mortalis battles located where no human and perhaps no Astartes could have fought and lived.In structure, the Covenants of the Ordo Reductor fought and operated as autonomous war bands, self-sufficient in almost all respects, containing a mixture of Magos and Tech-priest savants whose specialities ranged from tactical assault to macro-firepower to mimetic and forensic battlefield analysis to munitions production. Its weapons were many and deadly beyond reason, for to the Ordo Reductor was the right given to bear arms forbidden since the Dark Age of Technology and arcana deemed too unpredictable and dangerous for general deployment by the Great Crusade. Also, theirs by Dictate Imperial was the right -- within certain parameters -- to innovate new weapons and war machines in order to overcome the countless enemies the Great Crusade faced. This license bore fruit in many ways during the countless wars which made up the Great Crusade, from the development in concert with the Imperial Fists Legion of the peerlessly durable Land Raider Achilles, to the development of the powerful Eradication Cannon mounted on the Hellion-Minoris war machines of the Centurio Ordinatus, devised expressly for the Rangdan Campaign.Perahps the most widespread of the Ordo Reductor's creations is however the Thallaxii; heavily augmented cybernetic shock troops created by the Ordo Reductor to replace the Skitarii legions of Mars, to which, owing to their own separated status, they no longer had direct or ready access to for support. As well as serving first and foremost as the Ordo Reductor's soldiers of the line, the extremely potent and durable Thallax were also gifted or traded by the Ordo Reductor Magi to other factions of the Mechanicum as the Great Crusade went on, most notably to the Taghmata of Forge Worlds and outposts that were far separated from Mars, as well as elements of the Legio Cybernetica and the Myrmidon sub-cult (which often found common doctrinal cause with the Ordo Reductor) in return for reciprocal agreements of supply and allegiance. This served to both greatly increase the power and independence of the Ordo Reductor and, it has been argued by some, also contributed to the waning of Mars' direct military control over its outlying Forge Worlds in the solar decades before the Horus Heresy.