Tomes of the Librarius – Battlefields of Legend II: Cadia

Hello 40k fans! Chris Morgan, Chief Librarian of the Forge the Narrative Podcast, is back from hiatus to drop some knowledge bombs again with the next Tomes of the Librarius article. Also, be sure to check the Tactics Corner for more great articles!

Just as a reminder, in this series we will explore facets of the history and legends of the Grimdark. This is meant to be an easy summary and introduction geared towards new players or people unfamiliar with the setting, but should still be an interesting read or fun refresher for those already familiar. There’s so much detail in 40k lore that a bare summary seems so inadequate, but for new people this should be the right portion to get a feel for the history of the universe we enjoy our games in.

Keeping in theme for part two, this next segment will continue the ‘Battlefields of Legend’ series. We are continuing today with the planet Cadia. Where Armageddon was a planet of value to both humanity and the Orks, Cadia has a long history with the forces of the primordial annihilator, and would be the battlefield for some of the greatest wars that humanity would ever fight.

The Gatehouse of Hell

In the far reaches of space, a wound exists in reality. This wound rests at the heart of the ancient Aeldari empire, and is a rent from the catastrophic birth-throes of the god they came to call “She Who Thirsts.” This is called the Eye of Terror, and it is from here that the forces of chaos are most easily able to influence the corporeal reality of the galaxy. If the Eye of Terror is the gateway to hell, then Cadia was its gatehouse.

Situated at the mouth of the largest and most stable transit route in and out of the Eye, Cadia was constantly bathed in the view of that terrible realm’s nightmare energies. Mysteriously, the planet was covered in ancient black stone obelisks that defied all attempts to categorize and study. What would come to be known later was that these pylons held the wound in reality at bay, and prevented it from opening wider. At some point, the planet was colonized by humans in the days before Old Night, and after the Emperor’s Great Crusade began it was only a matter of time before this lost branch of humanity came into contact with the expeditionary fleets. Humanity would come to regret who ended up finding it…

The Coming of Lorgar

After his rebuke at the hands of Guilliman and the Emperor at the shrine world of Monarchia, Lorgar put his crusade into a frenzy. Outwardly trying to give an impression of change and obedience to his father, who shunned him for preaching of the Emperor’s divinity, Lorgar instead sought something new that would be worthy of his worship. This path would lead him to Cadia, where he came into contact with the humans living there.

The humans of Cadia long ago were primitive, and worshiped the gods of chaos. It was through them that Lorgar would come to know the ‘truth’ as he would later preach it, and come to worship the dark gods of chaos himself. In this, Cadia became a stepping stone on the road to the greatest civil war in the history of the galaxy. The war would come and go, but Cadia’s role in the fate of humanity was not over.


After their defeat on Terra, the traitor legions of Horus’ broken armada were hunted relentlessly by the victors. Harried and chased across the galaxy, most would pass by Cadia on the way back to the Eye of Terror, where they would hide in shame and defeat for many long years. For a time only the Black Templars – the fanatical offshoot of Rogal Dorn’s own Imperial Fists – held a constant vigil over the route out of the Eye, but it wasn’t until Abaddon began his black crusades that the Imperium realized it needed a bulwark against the nightmares of their pasts. Cadia was the best and most obvious choice.

The Cadian Gate and Its People

For thousands of years, Cadia stood as the first defense against the legions of chaos. The planet and neighboring systems were fortified and reinforced from all over the Imperium’s holdings, and the planet itself became (for all intents and purposes) a giant boot camp floating in space. Such was the tenacity and dedication of the troops who were bred and raised there that they became legendary for courage and discipline throughout the Imperium. The Cadian regiments would become among the most decorated and honored mortal warriors to bear the aquila, and time and again threw themselves at the nightmares the Eye of Terror would vomit forth, all in the name of protecting mankind from the ravening hordes of chaos. Cadia became the second-most heavily defended world in the galaxy, only eclipsed by Terra.

The Fall of Cadia

The story of the Fall of Cadia deserves an article of its own, but I will summarize it here. After thousands of years, the Black Legion achieved its goal and were able to break through the defenses of Cadia. Forces from dozens of Astartes Chapters, armies of Ecclesiarchal soldiers, billions of human auxiliaries, and thousands of warships fought against the tide that was the 13th Black Crusade.

During the fall, Saint Celestine would appear, a Necron would provide human reinforcements, and troops from the past would march with modern soldiers in the name of defending Cadia from Abaddon’s clutches. Abaddon would finally resort to throwing the shattered bulk of his blackstone fortress at the planet, cracking it asunder and destroying the black pylons that held the warp at bay. After suffering incredible losses, the heroes  of Cadia escaped, but the planet did not. It is now infamously declared among all the peoples of the Imperium that the planet broke before the guard did.

A Gate Shattered

Cadia has fallen, and the forces of Chaos pour from the Eye of Terror relentlessly. What does the future hold for the planet Cadia? It is hard to say. What we do know is that its memory will live long in the minds of its defenders and enemies alike.

I hope you enjoyed this week’s article! If you did, let me know in the comments below! What planet do you think is next in this series? What stories do you have from the Eye of Terror Campaigns of years gone by? I’d love to hear it!


Captain Morgan


About Chris Morgan

40K philosopher, LVO Judge, Chief Librarian of Forge the Narrative, Blood Angel enthusiast extraordinaire, and slayer of traitors, xenos, and heretics; I'd rather be playing 30k right now or neck-deep in a good book. Follow me on my FB page - Captain Morgan's Librarius

2 Responses to “Tomes of the Librarius – Battlefields of Legend II: Cadia”

  1. WestRider September 11, 2018 6:36 pm #

    Since I’ve just been reading through the Necron Codex, I was thinking that it was sort of a convenient coincidence that the C’tan/Necrons managed to build the focal point of their Pylon network right where the Eye of Terror would pop up 60 million-some years later, but then it occurred to me that the Eldar were one of the biggest threats that the Pylons were intended to cut off from the Warp, and the center of their empire was also where the Eye of Terror erupted, so it actually does make pretty good sense for them to be relatively near each other.

    • Reecius September 12, 2018 8:21 am #

      Yeah, that planet is/was extremely important.

      I also love how Be’Lakor went Leroy Jenkins on Terra, lolol. So good.

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