The most recent return to Imperial control was made by Saint Belisarius, who organised a Reclamation Crusade in the beginning of M37. Under his dynasty the Sector prospered and guarded the northern flank of the Imperium, remaining in Imperial hands for a longer period of time than ever before.
However as time has passed it has grown weak and corrupt. In the beginning of 41st millenium it suffered a series of very strong rebellions and civil wars that escalate with each passing century. Today no one but the Emperor himself knows what the future holds for this damned cluster of worlds.
The many threats Sector Deus currently faces are catalogued here: Threats in Sector Deus
Sector Deus is located on the Cygnus Arm in Segmentum Obscurus, less than 1,000 lightyears from the border with Segmentum Ultima. Like most Sectors, Deus forms a rough 200x200x200 lightyear cube, and subsectors of irregular shapes roughly 10-20 lightyears in diameter, with 50-100 lightyears of sparsely populated space between subsectors.
- Core Worlds - Subsector Deus
- Subsector Adamantis
- Subsector Aeternus
- Subsector Cryptus
- Subsector Dominus
- Subsector Ionium
- Subsector Meridian
- Subsector Mortis
- Subsector Tyranus
Demi-Segmentum Obscurus-3b is a portion of Segmentum Obscurus consisting of a few dozen different Sectors. The convention of Demi-Segmentum is mostly for astronomical convenience as few imperial institutions operate on a Demi-Segmentum level, but it may be used to describe the general area of operations for entities that span multiple sectors. Known Sectors in Demi-Segmentum Obscurus-3b are:
- Sector Deus - Located near the edge of the Demi-Segmentum on the galactic rim, Sector Deus has been on the frontier of the Imperium for thousands of years.
- Sector Corgus - The sector rimward of Deus, extending onto the galactic edge. This sector has been cut off by ancient warp storms since the Great Crusade.
- Sector Paxia - Located rimward and above the galactic plane compared to Deus, this sector has only a handful of populated systems.
- Sector Idaces - Located approximately 800 lightyears spinward of Deus. Sector Idaces was only first claimed for the Imperium in late M39, and so is not as well developed as older sectors like Deus. As such Sector Idaces is a hotbed of trade opportunities and colonisation efforts but also serves as a rich hunting ground for raiders - both human and xenos.
- Sector Morrux - Located approximately 2000 lightyears coreward of Deus. Sector Morrux is one of the oldest and most well developed Sectors in the entire Demi-Segmentum, numbering over 250 Imperial systems. Its most well-known system is the Forge World of Cassien IV, which produces & exports designs for local versions of machinery & starship components from across the galaxy for use in Demi-Segmentum Obscurus-3b. Examples include the Cassien-pattern Class 2a Drive, a sprint trader plasma drive based off the Lathe-pattern Class 2a Drive.
- Sector Brachau - Located approximately 1500 lighyears trailward of Deus. A recently re-discovered Sector that is currently the subject of a lengthy reclamation crusade that was launched by the celebrated Lord General Militant Moris Brachau in 153.M41. Though Brachau has since died the crusade carries on under the command of his protege, Lord General Militant Vann Khristoph. A sizeable battlefleet and thousands of regiments are engaged in the Brachau Crusade, and Imperial Guard forces from throughout the demi-segmentum have been drafted into it in addition to regiments from more famous worlds like Cadia, Krieg, Tallarn and Elysia. Much of Sector Brachau is still in the hands of xenos, renegades, and worse.