Coronid Deeps - Notable Regions: Coronid Prohibition Zone - An astra-navigational hazard of considerable size and uncertain borders, the Coronid Prohibition Zone, also commonly known as the Coronis Abomination and popularly to members of the Navis Nobilite as the "White Darkness." It borders the central northern edge of the Coronid Deeps region and, by popular wisdom among the void-faring, presents the most obvious reason for the dividing point of the ancient segmentae in Human stellar cartography. This apparently all-but-empty region of space holds up neither spectacle nor warning to either the naked eye or auspex, while in the Warp it apparently represents itself as "white out" to the Navigator's vision, akin to the blindness a man might encounter if trapped in a blizzard -- a literal "nothingness". The cause or consequence of the danger this region entails remains entirely unknown. By direct order of the Emperor, the Coronid Prohibition Zone was established, explicitly forbidding deliberate entry to this mysterious and deadly region of space, and a number of autonomous armed watch stations were created, roughly proscribing the region's borders. These stations establish and police the cordon around the zone, and dispatch Warp-capable hunter-killer Gholem-ships to engage and destroy any vessel or object detected leaving the zone.Coronid Reach - The furthest anchor point of Imperial civilisation in the region, the Coronid Reach is rightly regarded as the very edge of the dark frontier of galactic space, beyond which little may be said for certain. Its centre of power is the Hive World of Agathon, which dominates the region via its economic and military might, and represents the final conquest of the 60th Expeditionary Fleet during the Great Crusade, before its disbandment to settle the world it had claimed. This highly autonomous Imperial region comprises a cluster of sixteen inhabited star systems.Cyclops Cluster - The Cyclops Cluster is one of the most heavily industrialised sectors in the northern Imperium, featuring as it does within a single stellar volume two Forge Worlds as well as sixteen primary grade industrialised worlds and ninety-three distinct resource extraction zones. The Cyclop Cluster's economic output and strategic position is important to the larger Imperium. Though rich in minerals and ores, it is deficit in complex organics, with relatively few life-sustaining worlds among its stars.Cyclothrathe Holdfast - The former sovereign domain of the ancient Mechanicum, the Cyclothrathine Holdfast was founded on two of the few life-sustaining planets left in a desert of Dead Worlds wrought by the hand of the Great Crusade. Set up in the ashes of what were once the core systems of the xenos empire of the Mitu Conglomerate, the Holdfast was created both to oversee scavenging operations and to serve as a weapons-testing facility, as well as to ensure that all trace of the alien life forms which had made up the Conglomerate were utterly purged from existence. This region was ruled over by the Cyclothrathine Mechanicum, which had always been an insular and aloof sect of the Mechanicum. Even when it was still counted amongst those loyal to the Imperium, few were those who readily trusted its Tech-priests. They had garnered a reputation for ruthlessness and aggression, both in defence of their domains from any xenos that crossed the frontier, and in pressing any claims they made to resource rights and territory. During the Horus Heresy, the Warmaster Horus played on the jealousy and ambition of the Cyclothrathine Mechanicum to whom Mars was at best an unwanted and distant authority. Their name would become a byword for infamy and atrocity amongst the entire Imperium, as its position within the Dark Mechanicum and the reputation of its dire warlord, Archmagos Yelav Draykavac, were both cemented in the blood of countless planets.Grail Abyss - A celestial wasteland ranging between the galactic spiral arms, sparsely littered with stable star systems, rogue planets and the bled-out remnants of cosmic detritus and other shifting navigational hazards, the Grail Abyss is aptly named. Forming the extreme border of the Segmentum Obscurus and the edge of known space, beyond its borders lie only the drifting stars and systems accessible purely owing to the vagaries of relatively stable Warp passages from the galactic core (including such star systems as the now infamous Isstvan, and Ultima Ectosa, the furthest star across the northern galactic plane known to hold an Imperial colony). Owing to the shifting topography of the Grail Abyss, and the psychic emptiness in local Warpspace that gives it its name and makes predictable interstellar travel in the region unreliable, travel within the Grail Abyss is indeed more difficult in the main than reaching those furthest stars of Mankind, and likely was so long before the Imperium's birth. The Human-settled worlds of the Abyss are therefore few and far between, no more than candle-points flickering in a sea of night.Manachean Commonwealth - This aggregate of advanced and populated worlds, set at the junction point where the Segmentum Obscurus ends and the northeastern sweep of the Ultima Segmentum presses onwards to its outermost limits was, at the dawning of the war of the Horus Heresy, without doubt the most strategically vital area of the Coronid Deeps. Clustered with inhabitable stars, many of which had possessed Human colonist populations since before the Age of Strife, the Commonwealth served as a lynchpin of commerce and trade in this region of the burgeoning Imperium. Vitally, it was also a powerhouse of industry and military endeavour which held the shape of the burgeoning Imperium's borders during the Great Crusade. The two principal axes of this power in the region were the Manachea System itself, comprising several inhabited worlds with a population reaching into the many billions, and Port Maw, a colossal naval base still under construction when the Warmaster's treachery came to pass, and set upon an ancient artificial planetoid believed to be of xenos construction and vastly ancient, long predating even the rise of the Aeldari Empire in the galaxy.