Fall of Shadowbrink
|Conflict||Third Tyrannic War|
|Brother-Librarian Cadulon||Quadrifold Abominatum||Hive Mind|
| Grey Knights elements
2 Cadian Shock Trooper Regiments
1 Vostroyan Firstborn Regiment
6 Imperial Navy Destroyers
3 Orbital Defense Platforms
|Daemonic hordes||Hive Fleet Leviathan elements|
|Total annihilation, millions dead||Unknown, all defeated||unknown, likely high|
As Hive Fleet Leviathan drifted across Imperial territory, they soon reached the Cathedral World of Shadowbrink. The planetary government was reluctant to evacuate the world, for beneath Shadowbrink's capital of Rossov there was concealed a terrible secret. Discovered three decades earlier a ring of obscene archeotech from the Dark Age of Technology remained intact, dubbed the Maelstrom Cradle by Inquisition authorities. Though emitting fluctuated patterns of empyric overbleed and steadily strengthening Warp-signature, it couldn't be destroyed, so a permanent garrison of Grey Knights had been assigned to stand sentry over it, performing daily rituals of warding while their Librarians worked to seal the potential Daemonic rift. However with the onset of Hive Fleet Leviathan, it appeared the Grey Knights had run out of time. Yet their leader, Brother-Librarian Cadulon, could not permit evacuation while the chance of Daemonic incursion remained. Employing his exclusive authority, Cadulon instructed Shadowbrink's Governor to refuse the order to evacuate his peoeple, instead commanding the defenses of his world.
Due to Shadowbrink's importance, it did not stand defenseless. Alongside the world's Grey Knights, PDF, and Frateris Militia were two Cadian and one Vostroyan Regiments of the Imperial Guard. In orbit, Shadowbrink had three orbital defense platforms and six Cobra Class Destroyers for protection. However faced with an overwhelming assault, the orbital defenses of Shadowbrink were only able to hold out for three hours against the Tyranids. With the space above Shadowbrink clear, billions of Tyranids began to descend on the world, overrunning trenches and annihilating nearly every major settlement and city. Soon enough, the Tyranids were approaching the Maelstrom Cradle itself.
The Grey Knights deployed a pair of Dreadknights to meet the Tyranids, yet not even this was enough to stem the Tyranid tide. The Grey Knights, despite their efforts, were overwhelmed along with their Imperial Guard and PDF allies. At this point, the runes of the Maelstrom began to activate, gorged on the souls of the millions of humans dying around it. A Warp Rift opened up, and from it spilled vile Daemonic hordes. The Daemons were led by the dreaded Quadrifold Abominatum, a team of four Greater Daemons: the Great Unclean One Shub'Luth'Gug, the Bloodthirster Hak'Vasha, the Lord of Change K'rix'xi'kra, and the Keeper of Secrets Lesh'Jae'Thi'Hah. However almost immediately, the Daemonic advance began to fail when they discovered few Imperials left alive on Shadowbrink, driving the Daemon Lords into frustration at the lack of victims and souls to corrupt. However the Quadrifold decided to instead drive the Tyranids from Shadowbrink before turning their attention to the greater Imperium.
Up until this point the Hive Mind had utterly ignored the Daemonic forces due to their lack of consumable biomass. However this changed when a massive Impossible Fortress rose from beneath Rossov, holding millions of Daemons. The threat became too great for the Hive Mind to ignore, and combat between the Great Devourer and Ruinous Powers erupted. The Tyranids eventually controlled the plains around Rossov before launching an all-out offensive at the ruins of the city itself. However the Daemons unleashed a storm of bile and blood which turned the ground to muck, bogging down the Tyranids. Daemonic chariots swooped in on their trapped foes, as Furies and Plague Drones attacked from above. However the Hive Mind quickly adapted, throwing everything they had to distract the Warpspawn while swarms of Rippers rapidly consumed biomass elsewhere on Shadowbrink. This biomass was used to create swarms of Exocrines and Biovores which were in turn used to unleash devastating volleys of artillery to contain the Daemonic advance. Tervigons and the Termagants they unleashed were then deployed to launch a counter-attack through sheer attrition. The Great Unclean One Shub'Luth'Gug attempted to break the deadlock and push through, but his psychic abilities were smothered by the Shadow in the Warp. Moments later, the huge Daemon was blown apart by Zoanthropes.
With the defeat of one of their own, the Daemon Lords of the Abominatum realized the nature of the battle had changed. No blood was being spilled for Khorne, just putrid alien ichor. All of Nurgles diseases were ineffective in the face of Tyranid adaptation. The deadlock went on for days, and the Lord of Change K'rix'xi'kra blasted its way back to the Malestrom Cradle to abandon the effort. The two remaining Daemon Lords then led a final mad charge against the Tyranids. However the Hive Mind had by this point absorbed their opponents strategies, using Tyrannofexes and Trygons to meet them. The Daemonic lines soon collapsed, and as the Bloodthirster Hak'Vasha was dragged back into the Warp he was still wrestling with three Trygons. The last of the Daemons had been defeated, and the Hive Mind now turned its attention to the rest of Shadowbrink.