Eressa sector

Eressa sector is a sector located in the Segmentum Pacificus, and is partially under Imperial control. Plunged into chaos during the Macharian Heresies, the Imperium has since struggled to regain control, fighting not only against their own rebellious forces but also numerous Xenos.

Pre-Imperial history
Little is known of the earliest histories of the Eressa sector of space. During the War in Heaven, there were few battles that occurred within its bounds and it soon became relatively forgotten by the Eldar as the Necrons retired to their Tomb Worlds to hibernate. Over the course of millions of years, hundreds of species of Xenos would dwell in the planets of the Eressa sector, many originating in the Halo Zone or Veiled Region. Tens of thousands of years before the Imperium would come to exist the Eldar would return to seed worlds that would one day become Maiden and Exodite worlds.

Near the end of Humanity's 'Dark Age of Technology', human settlers first began to arrive. Many colonies would come under attack from various hostile Xenos and many of their creations would disappear or be destroyed in battles with nameless threats from the Halo Stars. Perhaps it is because of this that a few human colonies, such as Animos, survived the uprising of the Men of Iron. Those few worlds that survived, survived due to either becoming highly militarized, or by making alliances with some of the remaining and less hostile Xenos. Some time around M39 Orks would arrive in the sector, claiming entire systems.

Imperial conquest
In the years 332-339.M41 the Lord Solar Macharius would undertake one of the greatest conquests in Imperial history. Over the course of seven years nearly thousand worlds would be brought into the Imperium. Near the end of the seven year crusade, the Imperial forces would reach the Eressa sector, on the far edge of the Segmentum Pacificus and at the edge of the light of the Astronomicon. There they would discover a number of human-inhabited worlds, cut off for millennia from the rest of the Humanity. However, they also found a great number of planets and systems under the control of Xenos. Under the might of the Imperial Crusade, and against the genius of the Lord Solar, most Xenos fled and many human worlds surrendered rather than fought. Those who did not were ruthlessly crushed and either eradicated or subjugated.

After the death of the Lord Solar in 400.M41 however the sector would experience another 70 years of war as the Macharian Heresy spread across the newly conquered territory as the former generals of Macharius turned upon the Imperium, as well as each other. Carving out small star empires for themselves, it would take seventy years and the deployment of massive forces, including over one hundred separate Astartes chapters to quell the rebellions.

However, in the remote frontier sector of Eressa the damage had been done. As the generals fought against the Imperium, nearly all the Imperial forces left behind in the sector were pulled out to fight in distant battles. Those Xenos who had fled, as well as those humans who resented the new Imperial rule used this opportunity to retake the sector. By the time the Imperial forces reached the distant sector, much of it had either been retaken by Xenos forces, or was in open rebellion. By the time the main Imperial forces withdrew, only about 35% of the sector remained in Imperial control, the rest controlled primarily by various Xenos forces.

Imperium held

 * Tirithond - Imperial Sector Capital. Tirithond was the first planet of the sector to be conquered during the Macharian Crusade. What native Xenos culture existed was utterly razed and in their place were built dozens of mighty domed cities. Each city was built around planetary defense weaponry and the planet's colonists were brought in from Hive worlds in nearby sectors. Originally planned as no more than the first step into a new sector and a firm starting point, Tirithond became the center of Loyalists during the Macharian Heresy and was one of very few planets to remain loyal and unconquered until Imperial forces arrive. When the reclamation forces withdrew from the sector, Tirithond was declared the sector capital by the Adeptus Administratum, despite being on the eastern edge, as well as not near any of the sectors trade routes.
 * Beyonne - Located nearly centrally in the sector, the planet lacked any sentient life upon its discovery and was swiftly turned into a pivot for the supply of the crusading forces. As the fronts moved further and further away from Beyonne, its importance only grew, which would turn out to be a curse once the Crusade collapsed. Heavily fought over, the 'rulers' changed frequently while those in actual positions of power opted to not appear publicly. Under their shadowy rule, Beyonne became a center of enjoyment for the myriads of exhausted soldiers from both sides. Casinos and night clubs led to a wealth that eventually enabled the planet's rulers to buy their independence. Eventually, the Imperium reached Beyonne in the form of the Rogue Trader family Decebal. Against regular tithes in the form of Thrones and men, the planet has remained largely unchanged, still providing distraction and entertainment for all kinds of wallets in the sector.
 * Viunov system

Rebel held

 * Yaelea System - Though Yaelea IV has returned to Imperial hands due the efforts of the Astra Militarum, the rest of the system, Yaelea Primaris, Yaelea II and the majority of Yaelea III remain in rebel hands.
 * Chodounska - Located near the northern edge of the sector, Chodounska was a forward ammunitions depot during the Crusade and eventually left to its own devices after the death of Macharius. Set in a region haunted by frequent Xenos activity, the planet has recently entered the ownership of the Decebals, though they have yet to claim their possession.

Imperium
The Imperial presence in the sector has changed drastically over the course of the 41st Millennium. When the Macharian Crusade reached it, it quickly folded to the might of the Lord Solar's forces. After his death and during the subsequent Macharian Heresy, Imperial control would be shattered. By the time Imperial reclamation forces reached the Eressa sector, they would find desperate few places left friendly to the Imperium, the rest controlled by either rebels or Xenos forces taking advantage of the weakened Imperial presence. When the Imperial forces left in 470.M41 less than half the sector was under Imperial control. However they did not leave the sector unprotected, several planets had been instructed to raise regiments as tithes, many of whom would be used to protect the sector itself. On the ground or as part of the sector's beleaguered Battlefleet Eressa.

The Astartes' forces, fearing that the Xenos presence would endanger the western borders of the Imperium, would eventually find a Deathwatch Watch Fortress.

The many pieces of archeotech left by ancient human colonies ensured the Mechanicus would continue to maintain an interest in the distant sector.

Astra Militarum

 * Artemisia Armored- The first unit raised from the moon Artemisia VII, these men are true masters of armored warfare, proving their worth time and again in the ongoing campaign in the Yaelea system.  While a new unit, founded in 990.M41 they are nonetheless already well known among their Imperial Guard allies and the system's noble houses.


 * Beyonnian Dragoons - Raised from the numerous criminal biker gangs and racers of the pleasure world Beyonne, the Dragoons are a wild, sometimes unpredictable force favoring speed and mobility. Every soldier has access to transportation and the majority of them ride into battle on top of their heavily modified bikes and buggies. Their discipline is notoriously bad, but they are nonetheless an effective military force, striking hard and retreating before the enemy can retaliate.
 * Tirithond Titans - A Tempestus Scions regiment raised from the sector's capital, Tirithond, the Titans form the knife point of Astra Militarum forces in the area. While the capital's relatively low population (only about four billion) and large garrison limit the size of the regiment, the Tirithond Titans nevertheless preform their duties admirably.

Imperial Navy

 * Battlefleet Eressa


 * Battlefleet Eressa 616th Fighter Wing "The Ebony Grox" -  Considered the dregs of Battlefleet Eressa but also some of the best, only their considerable skills have kept these   men (pulled from various fighter wings and vessels) away from prison. Considered a nuisance to Battlefleet command for their antics and insubordinate attitude their current assignment is all but exile, designed to keep them busy, and far from anywhere they can cause trouble. Based on a planetoid in the remote Viunov system they are tasked with defending the surrounding area against pirates and Orks.

Deathwatch

 * Watch Fortress Malepertus - To counter the near-constant threat of the Xenos throughout the sector, the Deathwatch has established Watch Fortress Malepertus as a stronghold for the operations of their Kill-Teams. Carved from an ancient Space Hulk and outfitted with void shields and rows upon rows of defensive weapon batteries, Malepertus is not only the central presence of the Deathwatch within the sector, but also the main, public, base of operations for agents and Inquisitors of the Ordo Xenos.

Nobility

 * Household Decebal - Rogue Traders, the Decebals are relatively new in the grand scheme of things, but have quickly begun to establish themselves in a position of power. Overseen by a former general, they employ a militaristic mindset when approaching business and have, fittingly for themselves and the sector, specialized on trading in the many arts, weapons and services of war.

Inquisition

 * Black Tortoise Society - A private organization with strong connections to the Administratum, Militarum, Navy, Merchants and industry all over the Eressa Sector, its declared goal is to find and promote talents among imperial citizens. Ever since 500.M41, bureaus have been set up on many planets, recruiting from all ranks of society. Only a select few of the higher-ranking members are aware that the society is in fact an instrument of the Inquisition, it's countless members and associates working as informants and spies for the Eressa Conclave, often without their knowledge.

Orks

 * Boss Snazzgram's Gun Eatas - Led by the titular Boss, the Gun Eatas are raiders and pirates. Death Skullz heritage has equipped with a great number of Meks and Lootas, a combination which leads to their, unusual, focus on ranged warfare. While they still suffer from the typical lack of accuracy of any Ork, the sheer amount of firearms ensures that they eliminate their targets by sheer law of probability: if enough bullets are fired, some of them are eventually bound to hit. Bozz Snazzgram himself wields an Assault Cannon that was once mounted on an Astartes Dreadnought and has proven capable of overcoming strategy and tactics with firepower alone.
 * Da Meteork Skwadron - Painted in mockingly bright colors, the Speed Freaks of the Meteork Skwadron sell their lethal skills at high prices. Commanded by the unusually sly Kaptin' Zhodrukk, he has kept imperial pilots on their toes with the use of erratic maneuvers and inexplicably effective camouflage. Famously, the Skwadron has crossed swords with the 616th "Ebony Grox" on numerous occasions, causing a mutual rivalry.

Chaos

 * Janus Clique - A cell of ten Alpha Legionnaires operating throughout the Eressa sector, the Janus Clique has through blackmail and bribery nestled its way into the heart of the Eressa sector's governance. Operating largely through a vast network of spies, informants and human agents, the existence and goals of the Janus Clique remains largely unknown to the sector.