Grail Abyss



The Grail Abyss is a desolate streak of territory at the extreme northern border of the Imperium. It is a celestial wasteland locked between two galactic spiral arms where stable solar systems are scarce and rogue planets, energy bleed-outs, cosmic detritus and other navigational hazards are many. Sparsely populated, isolated it makes for one of the most dangerous regions of the Segmentum Obscurus. With the more populous sub-sectors of the Cyclops Cluster and the Manachean Commonwealth, the Coronid Reach and the Mechanicum-controlled domain of the Cyclothrathine Holdfast the Grail Abyss constitutes one of the regions of the wider Coronid Deeps.

Source



 * The Horus Heresy - Book Four : Conquest, pp. 10-11, 70-71