Vraks Prime was a Departmento Munitorum Armoury World and the site of the Basilica of Saint Leonis the Blind. It was beseiged in 813.M41, after the attempted assassination of Apostate Xaphan and subsequent siege of the Fortress of Vraks. The Imperial Guard's 88th Siege Army was raised from Line Korps of the Death Korps of Krieg. At the conclusion of the campaign to re-take the Basilica in 830.M41, Vraks Prime was considered a Dead World, and placed under an interdiction ordered by Inquisitor Lord Hector Rex.
Vraks itself was a barren and drab planet, covered in a layer of old volcanic dust. It was first discovered and logged by Imperial forces after the Age of Strife. A supply base was established by theRogue Trader Van Meer for stockpiling material for future expeditions around the rim of the Eye of Terror. It had a single starport, destroyed by the Dark Angels under Supreme Grand Master Azrael in 821.M41. This area was surrounded by a city of five million workers. Smaller settlements were scattered across the Van Meersland Wastes. It was part of a network of Armoury worlds across the Segmentum Obscurus used to stockpile arms and munitions for the Imperial Guard that would be needed in the event of a major incursion from The Eye of Terror, such as a Black Crusade.
The Fortress itself housed the headquarters of the Planetary Defence Forces, the Master of the Asministratum's offices, the Basilica of Saint Leonis, the Cardinal's Palace and the Citadel's own garrison barracks.