The Tellian Sector in M42

I'm launching an Imperium Maledictum campaign to try it out before I review it. Overall, doing the background work for the campaign so far, it's been pretty easy, and basically feels like a cleaned up and simplified Dark Heresy. I'm setting the new campaign in the Tellian Sector, but now updated to the 42nd millennium. This is a background document for the campaign.

The Tellian Sector: Overview

The Tellian sector is located at the furthest reaches of human galactic civilization, out on the cusp where the old Astronomican met the Halo Stars, far behind the Eye of Terror. With the division of the galaxy by the Great Rift at the end of M41 it is one of the darkest and loneliest sections of Imperium Nihilus.

The Tellian sector is a relatively new and small sector. It comprises only about a thousand settled systems under Imperial control, with all but the oldest and most developed systems dating about only to M38, about three and a half thousand years ago, and the majority of the smaller extractive colonies and agri-worlds settled within the past five hundred years. Explorator fleets from the Mechanicus continue to aggressively probe for new systems, while the major hive planets export billions of workers each year to scrape out their resources.

Despite its remoteness, the Tellian sector is of great interest to the Imperium because of the relative abundance of archaeotechnology, and though few would admit it, because of the abundance of xenotechnology that comes in through the Cold Trade. The Tellian sector is considered one of the best candidates to host an operational STC, the holy grail of the Adeptus Mechanicus.

Subsectors

The Tellian Sector is broken into four major subsectors that are stacked into a cube roughly 1000 LY x 1000 LY x 1000 LY. These subsectors are:

The Globe (Rising Spinward): A globular cluster that became the core of the Tellian sector, it was settled during the Great Crusade, nearly seven thousand years before the rest of the sector. The sector's highest levels of political and military authority emanate from it, along with power and wealth amongst the nobility. The most notable locations include the sector capital, Tellian Secundus, as well as the ancient Dyson Sphere called "Black Atlantis" of unknown manufacture. Approximately 40% of all of the sector's Imperial systems are in this subsector.

The Fog (Rising Trailing): Named after the nebular drifts found throughout this area, this section was a frontier of the Globe brought into Imperial Compliance in M38. The majority of the hundred or so Aeldari Maiden Worlds remaining in the sector are concentrated here, backed by the power of Craftworld Som-Daven. The Imperium mostly ignores them to focus on the Zul-Kan, a hostile xenos empire, with the Tertius crusade fleet of the Brazen Spears chapter (descended from the Black Templars) leading the fight. The Fog is also home to the first world with extensive archaeotech ruins discovered in the sector, Ildonth, which has become a penal world where slaves, rad-mutants, and servitors dig amongst endless fields of mud for glimmers of a former age's wonders.

The Wisp (Sinking Spinward): A thin smattering of ancient stars stuffed full of tombs and ruins, the Wisp was only settled between M38 and M40. Nearly 5% of the Imperial worlds here are Forge Worlds, and nearly a third of the subsector's other worlds feed their resources solely into them. Levi's Iris is a vast ringworld from the Dark Age of Technology built around a black hole that serves as the administrative centre for the sector's tech-priests. The Dour Guard space marine chapter (descended from the Iron Fists), the second of only two chapters operating in the entire sector, stand by at The Glare of Sebastus fortress-world.

The Cinders (Sinking Trailing): The trailing spinward sector. It is full of renegades, heretical cults, hereteks, psychic cabals, prospectors, infractionists, xenophiles, twist-lovers, Rogue Traders, profiteers, abominable intelligences, malign xenos, and other scum. Only about half of the 120 known worlds in this subsector are in the possession of the Imperium, and most were brought in during M41. Notable locations include the Yellow City, a vast stellar gantry run as a freeport for xenos and humans alike by mutants; Bhadra, where a recently discovered archaeotech fungus allows a single agri-world to produce 7% of the entire sector's promethium supply; and Qurmizi, a system lost entirely to the forces of the Black Dawn chaos cult.

(The Cinders is where our campaign will be set)

Touchpoints of History

The Silver Banner Asuras: A group of abominable intelligences wiped out by the Raven Guard space marine legion during M30 at the Battle of the Hollow Mind where their Matryoshka Cog-Moon was destroyed. Known for harvesting humanity and other species' neural mass to provide themselves with processing power and using the bodies as war-servitors. Many ancient space hulks are the results of their work.

The World Rush: The period between M38 and early M41 when most of the modern Tellian sector was conquered and colonized. This was driven by the discovery of the ruins of an ancient plasma reactor on the world of Ildonth that showed signs of being a first-generation STC product. In the course of three thousand years, nearly seven hundred worlds were brought into the Imperium, though most only became simple extractive colonies, research bases, or industrial worlds. Though a STC has never been discovered, a great deal of other archaeotech fragments have been, as have several Knight Worlds.  

The Zul-Kan Crusades: The Zul-Kan are a xenos race resembling a cross between owls and octopuses who control dozens of worlds at the border of the Tellian sector. Masters of gravitational manipulation, they appear able to hide many of their worlds from direct observation, and their home world has never been identified. Since late M38, the Imperium has been engaged in a series of inconclusive wars to find and eliminate their planetary holdings. Since the failure of the Astronomican, the latest crusade has been foundering and the Zul-Kan have taken the strategic initiative.

The Varosi Empire: The Varosi were a rare survival from the Dark Age of Technology, forming a powerful human empire that was only brought into Imperial Compliance in M38. Much of the empire's former territory was incorporated into the Cinders and Wisp subsectors, and the root populations of these regions, including the nobility, are mostly converted Varosi.

The Cardinals' War: The most significant religious conflict in the Tellian sector, this civil war between factions of the Ecclesiarchy was notionally about whether the Emperor had ever shed a tear without conscious intent, and practically about the supremacy of two cardinals for control of the sector's faithful and tithes. The conflict saw at more than a hundred minor sects declared heretical or schismatic across M40, but many escaped being purged and fled to the Cinders and beyond. Since the Noctis Aeterna and the weakening of the Imperium, many of these sectarians have been seeing explosive growth and are preparing to overthrow and replace the current Ecclesiarchy. 

The Mzod Purges: Originally declared a sub-sentient species of jellyfish-analogues, the Mzod are found on almost every world in the sector with large amounts of water. In mid-M40, they were discovered to be not only sentient, but powerful psykers and genetors. This led several planetary governors to try to eliminate them, but the Mzod released hidden caches of Ork spores that quickly led to the planets being overrun by rampaging hordes. The Mzod are still hunted by the authorities, but much more carefully, and their "strandtech" biotools are perhaps the most common kind of xenostech circulating through the sector.

The Statisticians of Certainty: A heretical sect of the Mechanicus who delved into temporal technology in mid-M41. They sought to travel to the future and return with advanced knowledge. They were discovered and destroyed by the Inquisition while operating in the Halo Stars just beyond the edge of the sector, but much of their forbidden knowledge is believed to remain scattered throughout datavaults in the Tellian sector. Many of the hereteks in the Wisp and Cinders derive from small remnants who escaped the purge. 

The Great Rift: The massive chaos rift opened twenty years ago and Imperial control of the sector has been in decline since. While the Astronomican was always dim and faded in the Tellian sector due to its position, its complete absence has led to a resurgence of the enemies of the Imperium. Through heroic efforts, the Administratum managed to prevent more than two dozen worlds from apocalyptic collapses from disruptions to vital trade. After about a decade of chaos, contact has recently been restored with the rest of the Imperium and word has come to the authorities of an "Indomitus Crusade" that is being launched to reconnect the lost sectors back to Holy Terra. 

The Empty Synod: Only recently identified by the Inquisition, the newest threat to the soon-to-be-resurgent Imperium is the "Empty Synod" or "Conventus Vanitas", a group of political malcontents, religious radicals, progress cult hereteks, psyker and mutant liberationists, and xenophiles who are infiltrating worlds and undermining Imperial control. High level reports claim that they are secretly run or supported by abominable intelligences, rogue psykers, and xenos of unknown origins, though it is unclear if the group is a Chaos cult or something even more nefarious at this point. The leadership of the group is believed to be based on a fleet hiding somewhere in the void between the stars in the Cinders. The Inquisition has formed a working group, the Ordo Vanitas, to stamp them out.

(The PCs are members of the Empty Synod)