Legio Cybernetica Background
The cult of the Machine God or the Adeptus Mechanicus is divided into many sub-branches divisions. Each specializes in one of the myriad areas of technical arcana. The Legio Cybernetica is one of the oldest of the Adeptus Mechanicus. Its records stretch back almost unbroken to the very first days of the Imperium. Legio is responsible for the care and construction of all Robots or Iron Warriors throughout the Imperium.

Iron Warriors are used by almost all the Imperium armed forces, but they are always under Legio's final control. Indeed, many of the Tech-Priest Engineers of the Legio have been killed while taking part in military operations. Legio continues to serve aware of its value as a fighting force, even in the face of 90% plus casualties. Legio is organized into several thousand cohorts, although a percentage of these is ever active at any one time. Each cohort is in turn organized into maniples of three, four or five Iron Warriors plus a Tech-Priest Engineer. The number of maniples in cohort varies, but is rarely more than 100. However, a cohort usually spread across an entire Army Group of several regiments. Battles involving more than 4 or more maniples are rare. This is not to say that they have never happened. Each maniple is virtually a self-contained unit. The (typically) three units are managed on the battlefield by a single Tech-Priest Engineer. He has little more to do than give the Iron Warriors their final programs and then monitor their progress. He is, however also charged with protecting damaged Iron Warriors making sure the Machine Gods property does not fall into the wrong hands.

Legio cohorts are occasionally attached to campaigning Marine Chapters, such as during Operation Carthage (the Second Pacification of Isstvan V). When the Desert Lions Chapter took the planet's defence forts they were preceded by a complete Legio Cohort of Iron Warriors. The Robots had been programmed to advance in an apparently mindless fashion, and proved easy targets for the defenders. However, the Desert Lions used the opportunity to map out the defenders' fire-plans and blind spots. In the Lions' ensuing assault only seven Marines were lost . All the surviving Iron Warriors were inducted into the Chapter as honourary members as a mark of respect.

The Inquisition at times has also put Cohorts of the Legio to good use. Iron Warriors are, by their very natures, utterly incorruptible. Their preprogrammed, non-biological natures make them the perfect troops to use against mutants and other contaminated populations. The terror value of Robots when used against unprepared and underarmed troops has not gone unnoticed by the Inquisition. This, combined with their unflagging loyalty, has made them valued additions to some Inquisitors armouries. Although many Inquisitors view the Iron Warriors with fear and suspicion, they do agree that Iron Warriors may be pure and incorruptible; men are not.

This was proven during the Horus Heresy, when many Legio Cohorts rebelled under the leadership of Warmaster Horus. Many of the Cohorts had been placed under the Warmaster's command in preparation for a new crusade. When Horus commanded his forces to move against the Emperor, the Legio Cohorts at his disposal were among those to obey. In the subsequent fighting many more of the Adeptus Mechanicus joined Horus and his rebels. Following the defeat of the Heresy and the banishment of the Traitor Legions, the dishonoured Legio Cohorts also fled into the Eye of Terror, where they remain to this day.

Another advantage is Legio maniples require less transport space than standard military units (Iron Warriors can be carried in open space without harm), less life support and food (Iron Warriors neither eat nor drink) and less battlefield support (Iron Warriors usually carry their own heavy weapons). Many Iron Warriors use standard armaments, reducing the need for specialized supplies. This makes them extremely popular with practical military commanders. Some of the older Cybernetica cohorts claim that their Robotic troops date, in part at least, back to the First Crusade of the Imperium and earlier. These claims may have some validity, as severely damaged Iron Warriors are often cannibalized to provide parts for their damaged brethren. Given the lifespans of Imperial technologies when maintained, such claims become reasonable. It is indeed possible that one Robot's leg, or cortex has been in almost constant use for more than ten thousand years.

Like a Dreadnought, an Iron Warrior is the product of the many advanced technologies which have produced its armoured shell, its artificial muscle and nerve bundles, its cortex, power plant, weapons control systems, equipment interfaces and cortex. The Mechanicus Weapon-shops turn out many Iron Warriors to the age-old designs held in the memory banks. The designs have remained virtually unchanged since that time, with perhaps only minor cosmetic variations. What makes an Iron Warrior different from an unoccupied Dreadnought suit is its cortex. This is an artificial brain of sorts, which is constructed from artificial proteins and enzymes. This cortex is imprinted with simple maintenance and movement routines - a rudimentary 'mind'. These enable the Iron Warrior to obey simple instructions (Open the Weapon Bay Door, Please... Move Ahead to the Holding Area etc) when away from the battlefield. These 'firmware' routines (so called because they are wired in' software) are often patterned after living creatures, and an Iron Warrior may develop a dog-like devotion to its Tech-Priest master. Before a battle the firmware routines are overlaid and replaced by the Iron Warriors combat wet-ware (ie the software of a protein computer).

This new cortex program, which can be changed for every battle, defines, for example, how and when the Iron Warrior is to fire its weapons. Each piece of wet-ware is held in a small slice of bioplastic, about the same size as a credit card. Many warriors take these from 'dead' Iron Warriors , believing that them to hold the soul and courage of the Iron Warrior. When kept in a medicine pouch some of the robot's bravery passes into the warrior; even some Marine Chapters have been known to follow this tradition. Without its cortex though a Robot is as helpless as a bolter without a Marine. It can do nothing other than take whatever punishment is meted out to it. With its cortex fully programmed, however, an Iron Warrior can prove itself the equal of many other creatures on the battlefield.