The new Grey Knights Codex has just revealed the details of a juicy mystery that’s been part of Warhammer 40k lore since 2011: the contents of the Terminus Decree. Locked in a humble wooden box that only the Supreme Grand Master of the Grey Knights is permitted to open, this edict was laid down by the Emperor himself, to be opened and enacted only in the event that all hope for humanity is lost: and now we know what it says.
According to the Terminus Decree, the Emperor of Mankind can never be allowed to leave the Golden Throne, “either returned to life, reborn in another’s body, or ascend as some kind of Warp entity”. Should that somehow occur, “the Grey Knights must return him to his terrible duty”, no matter what forces seek to oppose them.
Superficially, this seems like it’s there to stop the plot of Warhammer 40k from ever advancing, telling the audience that the Emperor is absolutely never leaving the throne. But the way that the Decree ties into deep lore and ongoing plot threads has incredibly exciting implications.
The metaplot for Warhammer 40k factions develops really, really slowly, and when Games Workshop resolves a mystery, it’s usually for a good reason. The description of the Terminus Decree is just a side bar in the latest Warhammer 40k codex release, but it ties into events from the Dawn of Fire novel series and the most important Horus Heresy books in a way that suggests this isn’t just fluff, it’s relevant to the metaplot.
Before you read on, be warned that this explanation involves massive plot spoilers from The End and the Death, plus two Warhammer 40k books, Guy Haley’s Throne of Light and Chris Wraight’s The Dark City, the final book in the Vaults of Terra trilogy.
While the Imperium of Man believes the Golden Throne to be a life support machine, and the thousand 40k psykers sacrificed to the Emperor every day are necessary to keep the Emperor alive, this is not strictly true. The Golden Throne is the Emperor’s own design made using recovered relics, based on an Akashic Reader (as seen in the novel Mechanicum). This was a Dark Age of Technology device that used multiple psykers to greatly enhance a central psyker’s ability to access the Warp.
The Golden Throne was integral to the Emperor’s Great Plan for humanity. In order to free mankind from its dependence on psykers for interstellar travel, he constructed a bridge between the Imperial Dungeon and the Webway, a subdimension that exists within but is isolated from the Warp. Originally made by the Old Ones, the Webway is what allows the Aeldari to travel the galaxy without exposure to the Warp.
The connection between the Imperial Dungeon and the Webway was broken when Magnus the Red attempted to warn the Emperor of Horus’ betrayal, crashing through multiple layers of metaphysical defenses with the power of sorcery. Disaster followed: catastrophic breaches opened within the Webway, allowing endless legions of daemons to surge forth.
The Emperor was forced to use the Golden Throne to prevent the damaged sections of the Webway bridge from completely collapsing, which would allow the daemonic hordes to invade Terra. First he attempted to stabilise the bridge so the Adeptus Custodes could attempt to clear the daemonic invasion and save the Emperor’s great work: then, after the Custodes were driven back, the Emperor was forced to use his strength merely in stopping the daemonic forces from breaching the Imperial dungeon. As the Siege of Terra wore on, this task became more and more onerous.
After Magnus’ Folly, Emperor physically left the throne twice: once to join the Custodes in the fight in the Webway, and once to take the fight to Horus on his flagship The Vengeful Spirit. The first time the Emperor left, a thousand psykers’ souls were required to fuel the Throne in his absence: when he went to face Horus, his ally Malcador the Sigilite, the second most potent human psyker ever to exist, gave his life to the throne, alongside countless lesser psykers.
So if the Emperor ever leaves the Golden Throne, Terra will be engulfed by daemons and consumed by a Warp Rift. And that’s not even the worst thing that could happen.
In the second volume of The End and the Death, the colossal three part novel which concludes the Siege of Terra, we see The Emperor’s attack on Horus’ flagship. It comes as reality is slipping into the Warp, in conditions similar to the downfall of the Aeldari empire and the creation of the Eye of Terror.
Horus is the conduit for all this energy, and the Emperor cannot defeat him with his own psychic strength alone. But he too can draw on the unlimited power of the Warp, and as he does so, he begins to ascend as a new Chaos power, The Dark King. This entity is an orb of blinding darkness, a force of utter annihilation, powerful enough to defeat Horus but the end of humanity and perhaps the galaxy itself should it prevail.
An encounter with his long-ago ally, the fellow perpetual Ollanius Persson stops the Emperor – not out of fondness or familiarity, but because the encounter is so unlikely the Emperor recognises it as the work of fate or something similar. Persson convinces him to use his deific power to truly consider what he is becoming: ultimately, the Emperor relinquishes the power, dooming himself to his fatal encounter with Horus.
Although the state of the Warhammer 40k galaxy is not quite as apocalyptic as Terra at the very end of the Horus Heresy, the Cicatrix Maledictum has allowed psychic energy to flow into the galaxy, causing an unprecedented number of psychic awakenings. In the Dawn of Fire novel series, and the Dark Imperium trilogy, we saints and miracles, which are either evidence of the Emperor’s direct intervention, or an extreme long game by Tzeentch.
The Emperor has more psychic power than he has had in living memory. It is possible that he may be on the path to ascension, and there’s no way of knowing what a deified version of the God Emperor of Mankind might actually be.
Nor is the Emperor strictly just one entity any longer. When the Emperor shed the power of the Dark King, he cut off and cast adrift the part of his soul that felt human emotions so he would not hesitate to slay Horus. Though he intended to retrieve this part of himself, he never did. It is possible that this entity is at work in the Warp, or that it has been reincarnated in human form – such as the Saint Sebastian Thor, who ended the reign of the insane tyrant Goge Vandire.
This soul-shard connects to a truly ancient piece of lore from the supplement Realm of Chaos: The Lost and the Damned, published in 1990. The details are a little different, but the book also states that the human core of the Emperor’s soul is cut adrift and lost in the warp. Known as the Star Child, this entity is key to the Emperor’s resurrection.
Just about every detail in the Lost in the Damned is no longer a reliable source, featuring concepts like the Illuminati secret society and the Emperor’s biological children, the Sensei, which haven’t been part of Warhammer 40k lore since 1993. But the Star Child has resurfaced in the lore since then.
In the Gav Thorpe novel Throne of Light, miraculous visions are traced to the astropathic relay on Srinigar, with both Imperial and Chaos forces rushing to claim it. In the final chapter, titled “Child of Light”, the historitor Fabian Gelfraine explains that the astropathic messages gathered at the relay contain “multiple references to a winged figure seated on a throne – that figure stands”.
The psychic Inquisitor Rostov, who was present at the fight for the relay, confirms he’s seen these visions as well. He cautions that there was once a Chaos cult known as the Cult of the Child of Light which had masqueraded as a resurrection cult of the Emperor. Yet Chaos forces – including Kor Phaeron, Dark Cardinal of the Word Bearers – treat the Child of Light as an existential threat. Again, if Tzeentch is at work here, it’s playing a very long game.
What’s more, we know from Chris Wraight’s novel The Dark City that the Golden Throne is failing and the Adeptus Mechanicus doesn’t know how to fix it. The Emperor cannot stay upon the Throne. And when he leaves, one way or another, it’s going to be Chaos.
Got your own theories about what’s really happening in 40k? Want to discuss any of the many related plot threads I haven’t mentioned? Come and join the chat in the official Wargamer Discord community.