Belis Corona Sector - 13th Black Crusade: In 999.M41, war came without warning to the Belis Corona Sub-sector. It was only two months after word arrived that Cadia was engaged in a war for its very survival that contact with the picket stations in Phonosar were lost. Three weeks later the battered Victory-class Battleship Warspite and two Cobra-class Destroyers from the venerated escort squadron "Torchbearers" entered the system with a pitifully small handful of transports, the sole surviving remanants of a vast flotilla tasked with defending the system. Having faced a vastly superior force, the fleet fought a desperate series of running battles while a rearguard straggled to hold back the invaders, but in the end nothing could prevent the fall of the system. With Phonosaur lost, it would only be a matter of time before Chaos would attempt to take the Belis Corona sub-sector in its foul grip. In only scant weeks, rumours abounded that the dreaded Slayer of Worlds once again stalked the sea of stars, and later is was speculated that Abaddon's two befouled engines of destruction escorted by the twin Despoiler-class Battleships Merciless Death and Fortress of Agony also once again had come to terrify the domains of men. It was only a matter of time before reinforcements and supplies coming to the system slowed to a trickle and then stopped, with nothing more in the way of explanation than a terse, pleading astropathic message fraught with horror. Cadia was under siege, and the long-dreaded 13th Black Crusade had begun.The opening moves by the Forces of Chaos saw large number of plague-ridden Space Hulks entering Imperial space. Though many were intercepted by the Space Marines and destroyed, some managed to escape the Astartes' attention. Some of these foul vessels of contagion found their way into the Belis Corona Sector, spreading their disease and pestilence amongst the masses throughout the sector. Along with the adjacent Agripinaa Sector, they were some of the first to bear witness to the rise of hordes of infectious, undead zombies that threatened billions of people on many of the Imperial worlds within the sector. This plague was later named the Curse of Unbelief.While the defence of the Cadian Gate from the Forces of Chaos continued to go badly upon the surface of many worlds in the Cadian System, in particular Saint Josmane's Hope and Solar Mariatus, the war in space was fought more on the Imperium's terms. The Cadian System had been the focus of Abaddon's primary fleet actions, and the Imperium's fortunes there changed from day to day. The situation was highly fluid and the Chaotic naval forces found themselves stretched to exploit the victories they had won.The inevitable sense of doom pervaded the worlds of the Belis Corona System, despite the Commissars' and military commanders' best attempts at maintaining the peoples' sagging morale. Laurentix was seized by riots in virtually all of its scattered mining settlements, and soon contact was lost with the world. Chaos Cults crying out to the End Times broke out on the Pleasure World of Belisimar, and it was all it could do for the Adeptus Arbites simply to maintain control. Despite these portents of doom, Belis Corona was not without its defences. It is home to vast orbital dockyards, decommissioned warship reserve fields and repair facilities that dwarf even those of Armageddon's St. Jowen's Dock in importance to the security of the Imperium. Due to its proximity to the Eye of Terror and its vital role in maintaining the fleets that guard the Cadian Gate, the system is guarded by a vast, integrated network of remote monitoring stations that orbit its sun just outside the orbit of blasted Malusoir.Under nearly constant solar bombardment, Malusoir circles its star in the shadow of the nearby Crown Belt, a dense cluster of asteroids noted for their high percentage of heavy, radioactive metals. Interference from the Belt created such a significant gap in the sensor network that the specialised monitoring station Adelphia was put in place to cover it. Holding a solar co-orbital position near Malusoir, it keeps a lonely vigil over the only sensor gap in the Belis Corona System, and the Mechanicus Adepts that maintain the station are the subject of routine visits by replenishment transports, system ships and the occasional Cruiser or Escort squadron on their way in or out of the system.As a Warp shadow fell over Subiaco Diablo System, indicating the imminent arrival of a vast Chaotic war host, terrified pleas for reinforcements were sent via garbled astropathic transmission to the fleet command at Belis Corona. More than forty vessels were mobilised and sent with great haste, leaving Belis Corona with only a reserve force of warships that was deemed sufficient to hold the well-defended system under the command of Admiral Guerrero Benedorn, an experienced and well-respected commander and veteran of the Curettes Pacification. When contact was lost with the scattered mining settlements on Laurentix, Admiral Benadorn directed an investigation be conducted with haste, and a party descending aboard the ore transporter Geniis Five reported that many of the settlements were abandoned without a trace of any of the personnel. Later, a survey team discovered grisly evidence of a coven of Chaos Cultists on Laurentix when investigating the disappearance of the entire population of Plainer, the largest mining settlement on the world. An urgent petition was sent by Astropaths for a Space Marine company to cleanse the world as critical preparations were undertaken to fortify the defence network of the system.