Descend far enough beneath the Imperial Palace on Terra — past the flooded halls, past the doors sealed in ages long forgotten — and the archives whisper of a place no primarch was permitted to see. There, in total secrecy, the Master of Mankind bent His incalculable intellect to a single purpose: the salvation of the species. It was called the Great Work, and it was the Emperor’s greatest concern above all else — above the Crusade, above His sons, above the war for the galaxy itself.
What follows is the tale of how that hidden project rose, and how it was ruined not by an enemy but by a son who loved his father, and who broke the world trying to warn Him.
The Great Work: The Emperor’s Secret Beneath the Palace
The chronicles are clear on the scale of the Emperor’s ambition. The devices that would form the project were removed from a desert and installed beneath the growing Imperial Palace, and there the Master of Mankind embarked upon His greatest undertaking. Its aim was breathtaking. As the archives record, His intention was to open the webway to humanity, removing mankind’s reliance on the warp at a single stroke.
Consider what victory would have meant. Had He succeeded, there would have been no more need for astropaths, no Navigators, no warp engines — no institution dependent upon the treacherous immaterium. Humanity could have turned its back upon the Warp entirely and concluded its evolution into a psychic species, safe from the depredations of the Dark Powers. To sever mankind from the Warp was to starve Chaos of its dominion over the human soul. This was no mere feat of engineering. It was war against the Gods, fought with tunnels and light.
The Golden Throne and the Unifiers
The webway is a labyrinthine realm between realspace and the Warp, a construct of the ancient Aeldari that spans the dimensions — a maze of glowing arteries walled off from the immaterium by psychic wards. The Emperor sought to graft a human road onto it. From a portal deep within the Palace, He ordered new passages built, and to that end He created a new caste of Mechanicum tech-priests, the Unifiers, to labour at the construction.
Yet here lay the fatal flaw. The archives note that these new tunnels were not forged of the psychically resistant material the Aeldari had used. Instead, the psychic will of the Emperor Himself, channelled through the Golden Throne, held back the daemonic tide. The Throne was never conceived as a life-support machine. It was, first and foremost, a device to permit human travel within the webway — an engine of the Great Work. That grim second purpose would come later, and it would come as a curse.
A Project Wrapped in Secrecy
After the triumph of Ullanor, the Emperor named Horus as Warmaster and withdrew to Terra. He gave His sons no reason. Not even the primarchs knew why their father had abandoned the Crusade at its zenith, and the sagas say this silence bred a slow poison of resentment — nowhere more bitterly than in the heart of the Warmaster himself, who felt abandoned by the father he worshipped.
Why such secrecy? The archives offer that the Emperor may have feared the Navigators, the Navis Nobilite, whose entire power rested upon their monopoly of Warp travel. A road that made them obsolete was a road worth killing for — and indeed, the sagas of the Path of Heaven tell how the Paternova’s hand moved against a prototype webway gate called Dark Glass, its fall contrived from within. Meanwhile the Aeldari, sensing intruders in their ancient roads, began sealing the portals to their own craftworlds against Imperial invasion. The Great Work was surrounded by enemies before its true catastrophe ever arrived.
Magnus’ Folly: The Warning That Doomed a Species
The ruin came from the most loyal of intentions. When Magnus the Red learned of Horus’s fall to Chaos upon Davin, he chose to warn his father the only way he knew — through sorcery, the very art the Emperor had forbidden him to practise. He cast his astral form across the immaterium toward Terra.
The account in Echoes of Eternity is damning and precise. Magnus’s astral form, swollen with righteousness and fuelled by human sacrifice, tore through the webway and ruptured its fragile protective sheaths. With every step, every breath, every sorcerous whisper, he destroyed more of the realm. He undid the Mechanicum’s Great Work towards the salvation of humanity, and he opened the way for daemonkind to flood into that sacred place. As the chronicle puts it with terrible finality: with a heart bursting with the best intentions, he had doomed his species.
His warning breached the Emperor’s carefully wrought wards. The Golden Throne, so the archives record, began to malfunction as the chain reaction spread. The webway portal deep beneath the Palace was torn wide, and through the breach the daemons came in numberless floods. In later years, gazing upon the burning ruin of his passage, Magnus would confess: ‘Had I known the truth, I would never have done what I did. Father should have told me.’ Vulkan’s reply was merciless — how could any brother have predicted that Magnus would defy the Emperor’s one command, and fuel his warning with barbarous sacrifice?
The War in the Webway
And so began the War in the Webway, a hidden engagement waged from the earliest years of the Heresy. It never appeared in the official histories of the age, yet it raged beneath the very heart of the Imperium. The Emperor despatched the Legio Custodes and the Silent Sisters to hold the breach, and the roll of the fallen is long: thousands of Custodians, Titans of Legio Ignatum, and heroes without number, set against daemon hordes and, at the last, the daemon-blade Drach’nyen — the End of Empires. The chronicle Magisterium counts the cost plainly: nine of every ten souls sent into that impossible realm were lost there.
Yet in Magisterium, Rogal Dorn names the campaign what it was: a fool’s errand. ‘Unless we committed everything we had, there was no hope of holding those portals,’ he told Constantin Valdor — and Valdor’s Custodians, bred to obey, would rather have died following a command than countermand it. The outcome was stalemate. The portal was sealed, the Great Work abandoned, and the dream of a Warp-free humanity died in the dark.
Why the Emperor Can Never Leave the Golden Throne
Here is the bitterest irony in all the annals. The Throne built to carry mankind into a bright future became the Emperor’s eternal prison. To hold the breach shut, He was forced to remain upon it, pouring His will into wards that only He could sustain. The archives are plain: only the Emperor’s power can keep the webway portal closed.
Valdor himself, in the last days of the Siege, said it plainly: the Emperor holds the breach under the Palace — and though the Mechanicum laboured for a way to release Him from that duty, it would not succeed in the time left to them. And Magnus, standing in the ruins of his father’s great work, finally saw what his pride had hidden from him. The Golden Throne — unearthed from ruins sunken deep beneath the driest desert, the lodestone that would have unlocked the secrets of the alien lattice — lay ruined, its impossibly complex dimensional inhibitors and warp buffers fused beyond salvage. Everything he had been so sure of knowing better than anyone else was a lie.
And so it stands. For more than a hundred centuries He has sat immobile, neither living nor truly dead, a god chained to a broken machine by the love of a wayward son. The road that was meant to free humanity from the Warp became the reason its saviour can never rise again.