Event · M41–M42

Gathering Storm

Gathering Storm denotes the sequence of events in 999.M41 that culminated in the fall of Cadia and the opening of the Great Rift. It comprises three closely linked episodes — the fracture of Biel-Tan, the fall of Cadia, and the rise of the primarch Roboute Guilliman — unfolding across the Cadian Gate in the eastern Segmentum Obscurus, the Ultramar world of Macragge, and, in its consequences, Terra itself. The sequence draws together the Aeldari seeress Yvraine and her nascent Ynnari faction, the forces of Abaddon the Despoiler’s Thirteenth Black Crusade, and the wider Imperium of Man, making it one of the few dated turning points to bind several major factions into a single chain of cause and effect. For ten thousand years Cadia had stood as the Imperium’s principal bulwark astride the Cadian Gate, the narrow warp route linking the galaxy’s northern reaches to the Eye of Terror, and had repelled twelve previous Black Crusades launched by Abaddon the Despoiler, former First Captain of the Sons of Horus. By the close of the 41st millennium, warp storms were multiplying across the galaxy, weakening the barriers between realspace and the immaterium. Among the Aeldari the death god Ynnead remained unborn and unawoken; the seeress Yvraine and the blade-adept known as the Visarch began gathering survivors of every Aeldari path into the Ynnari, a faction dedicated to awakening Ynnead fully through the harvest of the dying. Their return toward the craftworld Biel-Tan coincided with a surge in warp activity that the forces of Chaos exploited to strike at the Aeldari before they could regroup. On the former maiden world of Ursulia, bound to Biel-Tan by a webway route, the daemons of Khorne and Slaanesh gathered under the Bloodthirster Skarbrand and the Masque of Slaanesh, using the world as a staging ground to force the webway gate and fall upon Biel-Tan itself; the assault was checked only when the craftworld’s forces, joined by Yvraine’s Ynnari, sealed the breach. Abaddon meanwhile drove the Thirteenth Black Crusade to its climax at Cadia, where Lord Castellan Ursarkar E. Creed and the fortress world’s defenders were overwhelmed despite millennia of prepared fortification; Cadia’s destruction, and the failure of the psychic pylons that had long stabilised the region, tore open the Cicatrix Maledictum, the Great Rift, across the width of the galaxy. In the aftermath, the Archmagos Dominus Belisarius Cawl completed his long labour on Macragge to revive Roboute Guilliman from millennia of stasis, restoring the primarch to active leadership as the Imperium reeled. The opening of the Great Rift split the Imperium of Man into the Imperium Sanctus and the isolated, warp-choked Imperium Nihilus, ending the long equilibrium the galaxy had maintained since the Horus Heresy. Guilliman’s revival led directly to his assumption of the title Lord Commander of the Imperium and his launch of the Indomitus Crusade to relieve worlds cut off by the Rift; some accounts also describe the daemon primarch Magnus the Red, once master of the Thousand Sons and now bound to the Chaos god Tzeentch, reaching telepathically toward several Imperial minds during this same period of upheaval.

See where Gathering Storm occurred on the galactic map in the 41st Millennium.

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