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Warhammer 40K: Infamous Imperial Rebellions

7 Minute Read
Jul 4 2022

The Imperium is a big place and sometimes Planetary Governors and others decide they’d rather go solo. That’s when Rebellions happen.

The Imperium is a big place and rebellions against the Imperium happen all the time. Some of them are pretty well known like The Horus Heresy or the Badab War. Others are smaller and less well known like the Carnibales Rebellion which was a single planet or the Axonar Spirewar which was fought over a single Hive spire.

Here is our list of some of our favorite lesser known Imperial Rebellions – in no particular order:

Constantinus Iconoclasm


“In the wake of a war against an infesting Genestealer Cult, Nova Terra was plunged into anarchy by the renegade Space Marine Constantinus the Liberator, who renamed the world Constantinium. Following Constantinus’ fall to Chaos and the addition of several Chaos Space Marine warbands to his forces, he began a war of conquest in the surrounding Viridis sector which he eventually conquered after a campaign lasting ten years. Ultimately, Imperial forces led by the Iron Knights Chapter were sent to stabilize the area and reconquer the sector. Their campaign lasted 13 years and culminated with the death of Constantinus at the hands of the Officio Assassinorum.”

This is on our list because it has everything a good rebellion story needs. A “powder-keg” moment (the Genestealer Cult infestation), a good rebel leader (Constantinus the Linerator) and a bloody campaign both ways – 10 years for the rebels to “win” and then another 13 years for the Imperium to take it back. Classic Grimdark!

Macharian Heresy


“The Macharian Heresy was an event in early M41 in Segmentum Pacificus after the death of Lord Solar Macharius, commander of the Macharian Crusade. After the death of Macharius, the rivalry between his seven Army Group Generals erupted into a civil war throughout the newly-conquered territories. Eventually the swath of territory conquered by Macharius splintered into warring miniature empires, each ruled over by one Macharius’ old Generals, who abandoned their oaths of loyalty to the Imperium and opposed not only each other but also the authority of the Adeptus Terra. In addition, Space MarineChapters that took part in the Crusade came to blows over and petty disputes, such as the Doom Warriors and Inceptors.”

Lord Solar Macharius led one of the largest and most successful crusades since the Emperor himself. We’ve talked about it before – the Macharian Crusade is kind of a favorite around here. But the aftermath is the stuff of history! It took another seventy years and 100 Space Marine Chapters to come in and finally clean-up the mess. That’s a Rebellion for ya!


Delta Arbuthnot


This rebellion is nothing more than a footnote really. It’s “detailed” in the Hunt of Voldorius. Which is to say there isn’t a ton of info on it, but we wanted to mention it because it’s basically a Ratling Rebellion!

“Disaster struck the world, when a Alpha-level psyker forced the entire population of Ratling serfs, to rise up against the landowners in an orgy of bloodshed. The White Scars Chapter would later assist in putting down the rebellion.”

It’s like the Lollipop Guild in the Wizard of Oz rebelled and the White Scars have to zoom in a put them down. If that mental image doesn’t seem like a good Grimdark Rebellion, then nothing else will!

Faze V Uprising


“In the wake of the Nephilim Schism, refugees fleeing the wars afflicting the southern galactic rim came upon a region of space usually wracked with Warp Storms. However now, the region was curiously calm and a joint expedition between Rogue Traders and the Dark Angels 5th Company was dispatched. Upon entering the orbit of Faze V, the fleet was immediately fired upon by orbital energy weapons of an unknown type. The Dark Angels combat dropped to the surface, discovering men altered by cybernetic arts and controlled by some blasphemous machine intelligence. The Dark Angels cut their way through the machine-slave hordes, smashing the the massive logic engines of the central intelligence.”

When AI goes bad…This is another great snippet of Grimdark history. Faze V’s population was basically being controlled by a massive central machine intelligence. It took the Dark Angels 4 brutal months to put down this rebellion. And to muddy the waters just a little bit further, the Dark Angel Techmarines recovered some “undisclosed data” from the “core” before ultimately leaving Faze V to burn.


Good thing we can always trust the Dark Angels, right?! And speaking of rogue AI…

Moirae Schism


“The Moirae Schism was a major event in Adeptus Mechanicus history that took place during the Nova Terra Interregnum in M35. The civil war tore the Adeptus Mechanicus apart, dividing the Cult in ways unseen since the Schism of Mars during the Horus Heresy. The Moirae Tech-creed was based on the prophetic wave of calculations of a triad of tech-mystics enshrined within the rebellious Forge World of Moirae. The creed maintained that the beacon of the Astronomican contained hidden messages within its micro-fluctuations, and that these messages were from the Omnissiah and prophetic in nature. The Moirae Techpriests compiled these apocalyptic messages in their archives, copies of which quickly spread through many of the Cult Mechanicus‘ sub-sects. These radical teachings included references to the future overthrow of Mars and the fusion of the Adeptus Mechanicus and Ecclesiarchy. Such claims were treated as heresy by Mechanicus authorities on Mars, and civil war was quickly sparked between traditionalist and radical elements.”

The Adeptus Mechanicus has had more than a couple issues keeping it together over the years. Thankfully, the folks on Mars seem to be able to gather their strength and put down these internal rebellions – even if it does take 2000 years, several Titan Legions and Space Marine assistance to do it.

The War of Brass

“The Hive Worlds of the Gelmiro Cluster in the Calixis Sector fall into sedition, following the charismatic leadership of a figure calling himself the Emperor of Brass, debasing themselves into the worship of the Ruinous Powers. Heavily militarised, the renegades quickly sponsor and arm rebel groups on nearby worlds and when counter-attacked, reveal the hand of dark forces from the Eye of Terror in their ranks. The so-called War of Brass that followed was comparably brief but bloody, involving forces drawn from across the sector, and the involvement of the Adeptus Astartes and the Titans of Legio Venator, it rendered the once thriving worlds of Gelmiro blasted, rubble strewn rocks. Classified as War Worlds and the haunt of murderous scav-mutants, renegades and wreakers ever since, while the reign of the Emperor of Brass is long over, the system is still a shunned no-man’s land to this day.”

This one got out of hand in a hurry. Rebellions occur all the time across the Imperium and usually put down quickly by either the Arbites, Astra Militarum, or even the Astartes if if gets that far. This one was so serious, it brought in Titan Legions on the Imperial side, and involved massive Daemonic incursions alongside abhumans such as Scavvies.  Whoever the “Emperor of Brass” was, he sure made an enormous mess the Imperium has never cleaned up.

Bonus: Pacification of Sigma-Agrius


So you thought that the Ratling Rebellion was cute, huh? Maybe you thought that it was just a fluke? Well guess what – The Pacification of Sigma-Agrius was ANOTHER Ratling Rebellion! And this time, it wasn’t led by any one other than the Ratlings.


“The Departmento Munitorum calculated that a single Imperial Guardregiment would be sufficient to pacify the agricultural world as the Ratling rebels were poorly equipped and it is well known that the small abhumans lack any discipline. The leaders of the rebellion also realized this and the rebels fled to the hills as soon as the first assault ships began disembarkation of the 122nd Finreht Highlanders.

Colonel Serat, the commander in charge of the invasion, ordered the companies of the vanguard to form a defensive perimeter around the landing points to guarantee that the heavily loaded transports of the regiment could land safely. But upon making landfall, to their great surprise, they did not find any enemy.

They spent one week before the first contact with the enemy, when a patrol of Highlanders fell victim to snipers as they crossed a bridge on the Karline River. After being forced to retire, the Officer in charge called for reinforcements to pin and destroy the rebels who had conducted the ambush. That was the first incident of a war in which the rebels dedicated themselves to defend their world by guerilla warfare and lightning attacks. The Highlanders were forced onto the defensive during the many months before the High Command of the regiment ordered a change of strategy that totally horrified Colonel Serat and his men. The new orders required the Highlanders to devastate all the farms of all the towns that found with the intention of denying the rebels their means of subsistence and to thus attract them towards a battle which they could not win. The colonel accepted the necessity of a change of strategy and put the orders into effect.”

While the initial engagements were unconventional, eventually the Highlanders were able to squash the rebellion with overwhelming firepower. But this has severed as a warning to the Imperial Commanders on the planet for generations.

Learn more about Imperial Rebellions


Enjoy the history of the biggest Imperial rebellion of them all – The Horus Heresy

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