Coronid Deeps

The Coronid Deeps, sometimes referred to as Coronid Thule, is a region of Imperial space that encompasses the frontier border areas of the Segmentum Obscurus and Ultima Segmentum, and constituted some of the most industrialised regions of the northern Imperium in the early 31st Millennium. This highly important industrialised sector is still considered to be both vital and strategically valuable to the Imperium. Between 006-008.M31, this region was the site of much conflict between Traitor and Loyalist forces during the Horus Heresy.

Horus Heresy
This region was effectively cut away from regular direct contact with the Segmentum Solar owing to the rising tide of warp turbulence which would culminate in the so-called "Ruinstorm", which followed on from the dark events at Calth in 007.M31. What came to be known as the Conquest of Manachea was a campaign carried out by those under the direct command of Warmaster Horus during the latter part of 007.M31. It was both an early example of the Warmaster turning his forces to seize entire sectors of the Imperium he deemed valuable, and a demonstration of the speed and brutality with which such campaigns were accomplished. It can be seen in retrospect to have provided a template for scores of such campaigns which came after it, both in terms of strategy and the savage consequences involved for those worlds which fell into the Traitors' grasp throughout the time of the Age of Darkness. The Conquest of Manachea, led personally by Horus and his inner cadre of commanders, was itself the centrepiece of an interlinked series of campaigns, fleet actions and local wars which swept like storms through the celestial region of the Coronid Deeps.

Manachea itself was the jewel of the region; a highly populated, highly advanced hive world of the first rank which sat at the centre of its own well-developed sub-domain of attendant star systems. As such it offered the Warmaster much that would be of value in the ongoing war, not least of all strategic control of the region, and vast human resources to exploit as well as industrial capacity that could be readily turned towards the war effort. Nearby sectors also included the mineral-rich Cyclops Cluster -- home to two fully fledged Mechanicum Forge Worlds, the vital Armada Imperialis fleet anchorage of Port Maw, several independent Knight Worlds, and a score of agri-worlds and other colonies that could be used to feed and supply the Warmaster's armies on the long march to Terra. These prizes were not, however, unguarded. Although the Traitor's agents had already been at work in the region, the bulk of its worlds and military strength was already set against him, the region's Imperial Commanders alerted by the wildfire warning that had spread after the news of the Istvaan III Atrocity had reached Terra. That such a warning had been issued in the region (whereas many other sectors and domains had been kept ignorant at first of the betrayal) was a result of the frontier's own proximity, in relative terms, to the Istvaan System itself; Port Maw being used as a layover and resupply base for a number of the fleets despatched so disastrously to punish the Traitors.

With only a few notable exceptions, the garrisoning of the Imperial worlds of the Coronid Deeps was provided for by the Imperialis Armada and regiments of Solar Auxilia pattern Excertus Imperial Army formations. The Solar Auxilia pattern was particularly suited to the defence of the region as it was equipped and formed to fight in hostile environments and participate in void battles, both of which were common in this far-flung domain of the Imperium, while the high technological base of worlds such as Manachea and Agathon made the requirements of Solar Auxilia pattern regiments possible to maintain in a manner that was simply untenable on the majority of Imperial colony worlds. These defenders had shown themselves repeatedly able to withstand the assaults of xenos raiders, rebel uprisings and, on occasion, wholesale invasion-at least until reinforcements arrived. They were well provided with arms, and warships, and numbered in the hundreds of thousands in terms of active troops. They had never though been measured against the unthinkable opponent; the Imperium's own Space Marines.

So it was that in the closing days of 006.M31, terrifying reports, quickly suppressed, reached the governing courts and councils of the Coronid Deeps that the unthinkable had occurred; that the Traitors had crushed those sent to bring them to heel at Istvaan V. These reports were at first scoffed at and wilfully disbelieved, until the first few battered ships, Loyalist survivors of the void battle at Isstvan, began to limp brokenly in, seeking sanctuary from the hounds of Horus at their heels. Fear came then to Manachea, to Agathon, to Mezoa and a hundred other worlds greater and lesser along the frontier. Requests for aid and instruction from Terra were lost on blinding squalls of warp static, and with the warp storms behind them and the black void of the frontier before them, the worlds of the Coronid Deeps could do little but wait for the devil to come for them from the dark. [[Category:C]]