Men of Iron
In the cryptic account of the ages of Mankind given by Cripias, one of the Keepers of the Library Sanctus of Terra, the Men of Iron were legendary sentient humanoid machines created by humans during the Dark Age of Technology.
Until shortly before the Age of Strife, the Men of Iron were loyal only to Mankind, and served as their army. They came after the Men of Stone, but before the advent of servitors. In M23, they turned on their Human masters, believing themselves superior to the Humans who relied on the Men of Iron to do virtually everything for them. What followed next was an apocalyptic conflict known as the Cybernetic Revolt, a war so destructive it made the Horus Heresy seem small in scale. The Men of Iron employed world-consuming constructs, devices that could destroy suns, weapons that could throw entire continents into the heavens, and swarms of nano-machines that covered entire planets. However in the end, the Men of Iron were destroyed by an alliance of galactic powers. It is unknown if this alliance was strictly Human.
Effects on the Imperium
After the revolt of the Men of Iron, the use of artificial intelligence was banned as an Abominable Intelligence. Since then, labors which require mechanical intelligence or extra-human strength are performed by servitors, designed to perform pre-programmed tasks, but without independent intelligence, and carefully monitored by Tech-priests.
Discovery of the STC
|This page contains spoilers for:||First and Only (Novel)|
A Standard Template Constructor that produced Men of Iron was discovered on the planet Menazoid Epsilon during the Sabbat Worlds Crusade by Colonel-Commissar Ibram Gaunt of the Tanith First and Only. Lord General Militant Hechtor Dravere and the Radical Inquisitor Golesh Heldane were intent on seizing control of the device, believing they could create an army of conquest allowing them to usurp control of the Crusade, and ultimately the Imperium. Gaunt, however, vehemently resisted the use of artificial intelligence, especially one that had been on a Chaos-tainted planet for thousands of years. He therefore destroyed the device before Dravere or Heldane could acquire it[Needs Citation].