Five Layers of the Siege

The Siege begins earlier than the “Siege of Terra” itself: the traitor armada enters the Sol system, Perturabo strikes Pluto and Uranus at the same time, Luna falls, and only then does the orbital bombardment of Terra begin. If you look at Terra alone, you lose the entire sphere that the fleet pays for so that the walls make any sense at all.

The fall of the Lion’s Gate spaceport is logistics, not symbolism: the most heavily fortified port went to the traitors, Mortarion made it his headquarters, and four key points came under threat — the Colossi Gate, the Eternity Wall spaceport, the Saturnine Gate and the Gorgon Bastion. Saturnine is Dorn’s trap: Abaddon led the Justaerin into a gap that had been spotted, Fulgrim threw about a hundred thousand of the Emperor’s Children into the assault, but the ambushes of Loken and Garro cut down the Mournival. And the port will be recovered after all: later Khan retakes the Lion’s Gate and decapitates Mortarion, so that Guilliman’s reinforcements can land.

Mercury-Exultant is a no man’s land a hundred and fifty kilometres wide in front of the Exultant Wall, which joins the Inner and the Outer Palace. Legio Mortis first drove forward Titans raised by sorcery from among those destroyed at Beta-Garmon, and when Legio Ignatum had worn itself out on the dead, it struck with its main force and destroyed its old enemy. Without this frame the “walls” look like a minor infantry matter.

The fifth layer, invisible from the surface. The Custodians, the Sisters of Silence and the loyalist Mechanicum held the breach for almost ten years; when the Warp Titans crushed the walls of Calastar, the Unspoken Sanction was carried out — about a thousand psykers were sacrificed to the Golden Throne to seal the breach and thereby bind the Emperor to the Throne even before the last duel. In the finale Magnus comes to finish what he began and reaches the Throne itself — there Vulkan meets him and overcomes him, and together with the driving out of Angron at the Eternity Gate this breaks the traitors’ onslaught.

Horus lowers the shields of the Vengeful Spirit, luring the Emperor. The teleport boarding goes in four parties: the Emperor, Sanguinius, Dorn and the Custodians. Sanguinius is the first to reach Horus — and perishes, refusing to betray the Father; this is how the Black Rage is born. Dorn follows and is late not for the ship but for his brother. Then comes a duel across matter and the immaterium, a warp-force shed at the last instant, and Horus’s incinerated soul at the price of the Emperor’s mortal wounds. Several events on a single date are not a duplicate; they are layers of one hour.