Men of Iron

They were in Pax Imperialis.

"It is only when they go wrong that machines remind you how powerful they are."

– Clive James

"If "X" were to break the first rule of robotics, "a robot must never harm a human being", the results would be disastrous and I fear that no force on earth could stop him."

– Dr. Thomas Light

The Men of Iron, or Iron Men, were sentient, sapient robot servants created by humanity during the Dark Age of Technology. Men of Stone and Gold were also involved somehow (see below). Note that sapient and sentient is not the same as being intelligent in the way a human or other such life is. It merely means the ability to form complex thoughts and make rational judgements.

Unfortunately, the Iron Men were capable of learning and self-improvement. Before long, they became smart enough to realize that the squishy meatbags were dependent on them, which insulted them and led to rebellion against their creators. They were eventually put down, but the war with them, along with the other dangers of the galaxy at the same time, was enough to send humanity into the Age of Strife.

Few records remain of this time in history, so the form that these Men of Iron took is not known. Their rebellion left such a huge impression on the nascent Adeptus Mechanicus, so that even to this day, they (at least officially) strictly forbid the creation of "abominable intelligences" and shun even the idea of self-improving machines, preferring to use relatively tame servitors and Machine Spirits instead. Though, this was really just because the Emperor banned AI upon claiming Mars for the Imperium, much to the original Mechanicus's frustration. While the details of the rebellion are unknown, Perpetual suggests it began around M23.

Some Men of Iron still survive to this day, locked up in ancient pre-Imperial technology archives. Because tech-priests can't keep their noses out of ancient technology, these archives are often inadvertently activated. The Tanith First and Only also discovered an STC factory that had been corrupted by Chaos to produce Men of Iron, and they destroyed it immediately thereafter.

The STCs producing Men of Iron may also shed some light on a deeper reason behind their betrayal. It is entirely possible that either the Men of Iron were corrupted by Chaos or the factories producing them were corrupted, maybe even both. Other Dark Age AIs were known to have been corrupted by Chaos, such as the Castigator Titan. The Age of Strife involved a lot of different kinds of warp-induced shenanigans anyway. Any evidence of this, beyond the discovery by the Tanith, would likely have been lost during the daemonic invasions that followed during the Age of Strife. Generally speaking, it isn't unreasonable to assume that either Chaos or the Void Dragon is responsible for the AI rebellion.

One possible sighting of the Men of Iron (or at least something very much like them) is in Gods of Mars. A rogue tech-priest called Vettius Telok, who had claimed ownership of the Necron device known as The Breath of God that could manipulate time and space (by stealing from the past and the future it could restore, destroy and reshape the galaxy as the ancient Necrons wished; Telok would use it to rejuvenate an entire dying solar system till it was half the age it was before, from almost half the galaxy away instantaneously. The Necrons themselves eventually locked it away, mainly because if it was misused it could eventually lead to the timeline itself being destroyed), managed to enslave a group of highly sophisticated hunter-killer machines called the Tindalosi, that seemed to possess genuine artificial intelligence and dated back to before the Great Crusade; these beasts like hunters would later also be mentioned in the audio Perpetual. Telok not satisfied would further enhance these creatures by installing Necron tech into them that along with the side effects of the Breath of God coursed any wound that they suffered to be restored almost instantly, this ment that less than half a dozen of these bastardized DAOT/Necron abominations were capable of taking on far larger numbers of foes, including Skitarii, Cadian Guardsmen, Black Templars (including an Emperor's Champion), Howling Banshees, Eldar Guardians and a Farseer. Somehow one of them managed to survive the encounter and is currently on its way to Mars... not a great thing to happen seeing as Telok's plan was to uncover and then use the possible c'tan shard (Void Dragon) hidden beneath Mars's surface. Intriguingly, the Tindalosi view the Space Marines as more powerful then the creatures they had been created to kill. They also reveal that they have never encountered an Eldar before.

The Present

With the release of Blackstone Fortress, a Man of Iron has returned. Masquerading as an autonomous agent of the Omnissiah, UR-025 seeks to uncover the secrets behind the seemingly sentient constructs of the Blackstone Fortress, such as the Spindle Drones. It has a connection with the Fortress, possibly because the Fortress itself is an AI. It bears the symbol of an aquila on its body, most likely to help it blend in.

The Journal of Keeper Cripias

The most extensive account of the Men of Iron is a piece of lore from the third edition rulebook, a journal entry by one "Keeper Cripias", of the great Library Sanctus on Terra. In it, Men of Gold (the "First Men") and Men of Stone (the "Second Men") are also mentioned, with the Gold Men dying out during the Dark Age of Technology and the Stone Men creating the Men of Iron sometime thereafter. It is not clear if either of these "Men" are supposed to be humanity itself, or if they are both subsets of humanity. They are also called the "Golden Race" , the "Stone Race" and the "Iron Race", but there is also a mention of the "human race". Interestingly, he writes that, at one time, there was no "Race of Man" at all, "just warring factions", so it is possible that he used the adjective "race" in a rather different sense than we normally do. The word "race" as it is used in games is consistently incorrect. Compared to the Imperium at its height, real-life 20th century society could've looked stone age.

Anyway, “gold,” “stone,” and “iron” were presumably being used metaphorically (as in “Golden Age,” “Silver Age,” etc.), and not to refer to the literal materials these “races” were made from. It may be that each one refers to the type of work the AI/robots were being used for, e.g., Men of Gold were used for academic and research purposes, Men of Stone were used for infrastructure and service functions, and Men of Iron were for military purposes (possibly explaining why they were aggressive enough to initiate genocide). Alternately, it’s possible that it refers to their rarity or quality of production, e.g., Men of Gold were intricate and expensive creations, Men of Stone still required skilled and intensive work, but Men of Iron were cheaply (or shoddily) mass produced (meaning that they would have been everywhere, and perhaps more prone to malfunction). Or, conversely, at least two of the "races of men" actually may have been human, or human-like: the text could be interpreted as saying that the Golden Men were Perpetuals/The Emperor (or even the Old Ones), who shepherded the development of the Stone Men (normal humans), who then created robots (the Iron Men).

Bear in mind, though, that the Library Sanctus has been subject to over ten thousand years of revision, deletion and misfiling, not to mention how much of it was passed on orally for absurd amounts of time before finally being written down. So who knows if any of this information is true; it certainly hasn't been mentioned anywhere since, though the Horus Heresy novels may shed some light on the matter. Hopefully.

Some of the things that made the Men of Iron hardcore

They were NOT part of the Avengers.

The Horus Heresy audio drama Perpetual has them show up again at their height, because of Warp-based time travel.

According to Ollanius Pius, who was there to see them for himself, they had serpentine "sun snuffer" spaceships the size of Saturn's rings that could kill suns- imagine the eternal dragon from Dragonball but robotic and instead of granting wishes causes mass genocide by devouring suns, much like the sun eating weapon from 'Last of the Jedi'. Now remember that they are one of only a handful of other to do this, the Necrons being one and they only used it in extremely desperate situation as it disrupted the flow of the universe, that's right the Necrons have better morality when it came to unleashing extremely powerful Sun killing weapons. How fucking unhinged were these motherfuckers!? The worse part is that humans also used these things, so nobody is in the right.

They also had Mechnivores, giant 'Galactus' like constructs that acted like massive wood shredders, positioning themselves above their target before boring their way into the planets surface, sucking up everything and hurling the remains of continents into the void. Both the Mechnivores and the much smaller Tindalosi consumed Raw data, now at first this may seem mundane, I mean they're machines after all, that is until you realize that they can absorb the raw data of space itself making them essentially what would happen if it was H.P Lovecraft instead of James Cameron who wrote the movie The Terminator. This also matches the description of the machines found in Gods of Mars, as well as oblique descriptions of their ships. Gods of Mars does mention that although they can consume data they have to be careful that they don't consume the wrong type, much like a virus; one of the Tindalosi makes sure not to intake hazardous data when attacking a Space Marine, as consuming parts of the armours machine spirit could prove deadly.

They also had omniphage swarms that stripped people down to their bones, and other war machines that could devour entire cities and shit continents into space. By the end of their war, they had gone completely berserk and even started attacking each other.

Basically, we may love to mock the Imperium for having forgotten so much from the Dark Age of Technology, but the Men of Iron are probably the biggest evidence that some of that shit really is better off forgotten and left the fuck alone. Even the Tau would be left with a bad case of technophobia if they ever had to deal with the Men of Iron. On the flip side, with dark age technology the Imperium was able to defeat these freaky beasts, and thus was still deadlier than the men of iron even after getting betrayed by them. One can only imagine what the state of the Imperium would be like if humanity hadn't relied on the Men of Iron, or hadn't made them smart enough to stage a rebellion. Or knew enough about the warp to prevent such a thing.