The Siege of Vraks was one of the longest and most terrible campaigns of the 41st Millennium, a seventeen-year struggle to reclaim a single armoury world lost to heresy. Vraks was a vast Imperial depot, its surface a labyrinth of bunkers and munitions stockpiles, until an apostate cardinal seized it and turned its defenders against the Imperium.
To retake this treasure trove of weapons, the Imperium dispatched the grim siege-masters of the Death Korps of Krieg, Guardsmen who embraced attrition and self-sacrifice as articles of faith. What followed was a nightmare of trench warfare on a planetary scale, entire generations of soldiers fed into fortified lines that barely moved for years. Artillery duels, tunnel fighting, and gas attacks made Vraks a byword for grinding misery.
As the siege dragged on, the renegade garrison fell ever deeper into damnation, and their prayers eventually drew the attention of the Ruinous Powers. Traitor Space Marines and summoned daemons entered the fray, transforming a war against heretics into a battle against Chaos itself. The world was ultimately reclaimed, but only after immense slaughter had rendered its surface a poisoned graveyard. So corrupted had Vraks become that it was left a quarantined ruin, its hard-won stockpiles a monument to the appalling cost of the Imperium's victories.