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Warhammer 40K: Iconic Wars of the Astra Militarum

7 Minute Read
Nov 21 2022


The Astra Militarum has had an amazing array of wars and their history runs deep – let’s take a look at the most famed battles that defined the Imperial Guard!

War is a constant in the Grimdark. The Imperium has it’s Angels of Death and it’s Forge Worlds but the true strength of Terra lies with the billions of souls that enlist in the Imperial Guard: The Armies of the Astra Militarum. The life expectancy of a Guardsmen is short but their sacrifice is what protects the rest of humanity from all of the threats in the universe. They fight chaos, the traitors, and the xenos. And most don’t live to tell their tales…

Within all that history there are 5 wars that we feel are the most iconic. Maybe it was a particular hero that arose from that war or maybe it was just the sheer determination the Astra Militarum showed – whatever the case these are the battles we think of when someone says Astra Militarum!

Macharian Crusade

The Macharian Crusade (392-399.M41) was a seven year campaign (or Crusade) led by Lord Commander Solar Macharius. It took place on the far western edge of the galaxy, within the Segmentum Pacificus and leading into the Halo Zone. The campaign brought nearly one thousand worlds into the Imperium, and was one of the most successful crusades in its history. Since the end of the Crusade there has not been a crusade of such success, or size.

We have to start our list off with the Macharian Crusade. It was kind of a big deal because it was the most successful crusades in the history of the Imperium. And it was led by Lord Solar Macharius who was “just a man” and not a genetically engineered super soldier. Had one of his trusted retinue not betrayed him who knows how much farther he could have gone in the name of the Imperium.

The Macharian Crusade showed that the Guard are more than capable of going on the offensive and reclaiming territory. They are NOT just a planetary defense force – they can be a hammer as much as the anvil when the need arises.

Second War for Armageddon


The Second War for Armageddon is the second best known of the three wars of the system. It took place on the Hive World of Armageddon between the mighty Ork Warboss Ghazghkull Mag Uruk Thraka and the forces of the Imperium and included regiments of the Imperial Guard and Space Marines of the Blood Angels, Salamanders and Ultramarines Chapters, along with a large Squat army. It would see the planet being swarmed with green-skinned Orks of five different tribes. The main war lasted for two years, but the actual combat continued for the next twenty years, a colossal effort for just one planet.

Why the Second War for Armageddon and not the Third War? Because the Second War is where the Legend of Commissar Yarrick begins.

Yarrick himself was always on the front lines during the fighting. He received many battle wounds, the most grievous in single combat with WarbossUgulhard, who severed Yarrick’s right hand with a swipe from his Power Klaw. Such a wound would have killed a lesser man, but Yarrick’s iron will allowed him to not only survive, but to decapitate Ugulhard with his chainsword and then pull the Power Klaw from his corpse and hold it aloft for all to see. The sight caused the Orks to flee in terror, while simultaneously causing the human defenders to charge forward with renewed vigour. Only after the Orks had been routed did Yarrick allow himself the luxury of passing out.

Yarrick is the Commissar that everyone thinks about then you say the words “name an Imperial Commissar.” That by itself should explain why it’s the Second War for Armageddon that is more iconic than the Third.

Siege of Vraks

The Siege of Vraks was a major campaign waged by the Imperium to reclaim the world of Vraks, first from traitorous forces, and later from Chaos.

On 414830.M41, the Siege of Vraks officially ended. 14 Million Krieg Guardsmen and hundreds more Space Marines, Titan Princeps, and Inquisitors had lost their lives. The original goal of the mission, to retake the planet from the rogue cardinal Xaphan reclaim the worlds armouries were theoretically completed. However while in Imperial hands, the taint of Chaos lingered and the planet was quarantined by the Inquisition. The world was too ruined to be of much use anyway, its armouries used up in the war. Thus it remains that Vraks is a barren wasteland, though the Ordo Malleus has conducted long reviews into the events of its war.


This one is on the list because 1) The Death Korps of Krieg are…insane and 2) it shows that sometimes it’s just the sheer willpower of humanity that pushes against the forces of Chaos. 14 MILLION Krieg Guardsmen died. That might just be a drop in the bucket when it comes to the sum total of the Astra Militarum, but it’s that willingness to throw lives at a problem until it’s declared “finished” that is truly scary. But that idea is part of the Imperium. In the Astra Militarum life is cheap and only victory matters.

War of the Beast

The War of the Beast, also known as Waaagh! The Beast was an enormous OrkWaaagh! first encountered by the Imperium in 544.M32. Waged by the Warboss known only as The Beast after he succeeded in uniting much of the Ork race, his Waaagh! was the largest the Galaxy has ever seen and rampaged across the Imperium, eclipsing even the one Horus defeated during the Ullanor Crusade which earned him the title of Warmaster. The largest war fought by the Imperium since the Horus Heresy, humanity only halted his advance at great cost and desperate measure, devastating the Adeptus Astartes.

We picked the War of the Beast because it shows that the Astra Militarum can get bodies faster than just about anyone else in the galaxy. They recruited billions to fight in this war. Human losses were high – and in spite of the infighting and the fact that Space Marines got the credit for the ultimate victory, it was on the backs of the Astra Militarum that the Orks were stalled. Think about it – if every day citizens had not fought against the orks invaders, the orks would have moved through the system like the massive green tide they are. They would have swept up Terra in their orky-wake.

13th Black Crusade

The 13th Black Crusade of Abaddon the Despoiler began in 999.M41, and resulted in the largest mobilisation of both Imperial and Chaotic forces seen since the Horus Heresy.

Abaddon’s strategy was based around the concept of The Crimson Path: by summoning enough Daemons to the surface of Cadia, he intended to overload the Pylons holding back the tides of the Warp on the planet. If he should succeed, the Eye of Terror will envelop Cadia and transform it into a hellish Daemon World, after which Abaddon intends to jump from planet to planet from the Segmentum Obscurus, until Terra itself is swallowed up into the Eye.

We had to mention the 13th Black Crusade. Why? Because it drastically impacted the Imperium, changed the status quo, and set the stage for how the guard are going to move forward. The Cadia Gate is no more. But despite the loss, the Astra Militarum fights on! That’s why the 13th Black Crusade is such an Iconic war for the Astra Militarum – Cadia Stands!

Siege of Hydra Cordatus


The Siege of Hydra Cordatus took place in late M41, when a battle-force of the Iron Warriors Chaos Space Marines besieged the Imperial fortress on the Forge World of Hydra Cordatus. The Iron Warriors had been ordered to take the fortress by Abaddon the Despoiler, seeking to recover the hidden store of Imperial Fists‘ gene-seed inside the fortress, as part of his plans for the impending 13th Black Crusade. Under the overall command of The Warsmith , the primary Chaos commanders during the siege were Forrix, Honsou, and Kroeger.

The Siege of Hydra Cordatus is included as it is an exemplary battle showing the determination and grit of the numberless Astra Militarum in a hostile universe surrounded by monsters. Regardless of the odds, and in the face of the Chaos Marine companies of the Iron Warriors Legion the Astra Militarum fought on. At the battles end, the forces of Chaos fled. While around them loyal Space Marines, and even titans fell to the last – the campaign’s sole survivor was a lone Astra Militarum Guardsman.

Learn more about the Battles of the Astra Militarum 


Do you have a favorite battle or war that springs to mind for the Astra Militarum? Let us know in the comments below!

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