Gemini is the super-moon of the Mining Death world of Oblivion, and is one of only two bodies in the Duos Sphereres system. Unlike its slightly larger parent planet, Gemini at a distance is wholly unremarkable, apart from its massive size in comparison to Oblivion, appearing as little more than a barren grey dust ball connected onto its twin by the many if unstable gigantic volcanic pillars. However the upon closer inspection Gemini appears both tectonically stable and extremely peaceful for a world with no atmosphere, despite the nearby world it orbits having a gravity over ten times stronger than Terra.
The reason for this is due to the existence of a series of massive and ancient stasis generators that have effectively fixed the planet in orbit around Oblivion and rendered the strong gravitational effects that Oblivion would exert on it mute.
As such while Oblivion is torn apart by Gemini's gigantic mass, the moon seems completely untouched by the normal laws of physics excluding the many snaking paths down to its neighbor and the many meteor shower it suffers on a daily basis. In spite of this though and its lack of atmosphere Gemini has seen repeated waves of colonization from a variety of species due to the ore rich nature of Oblivion and the only route down to the planet existing on Gemini. The latest wave of Colonization was under humanity who through assistance of an undocumented Space Marine legion managed to drive the Xenos off Gemini claiming it for the Imperium in 848.M30, and has since remained an obedient and valuable world to the Imperium.
Gemini before the Great Crusade was a major mining world for the small Xenos empire belonging to the now extinct Halarume species. The Empire itself was large enough to be considered a threat and as such was assigned for elimination as per-standard protocol during the Xenos Crusade. Even back then though tales of the mineral wealth of Oblivion led to the area becoming a prime target during the invasion of the Halarume territories.
The first attack wave on the planet was led by a detachment from a Space Marine Legion around 300 men strong, along with a 400,000 strong deployment of various regiments from the Imperial Armies ground forces. The first assault managed to destroy the Gemini's Xeno's defense force and quickly eliminated most of the habitats nearer the planets surface. With the Imperial Navy quickly destroying any possible reinforcements from reaching the planet, with the Space Marines quickly being moved onto the species home world.
The planet itself underwent numerous waves of invasions as to purge the remaining Halarume hiding in Gemini's many twisting and snaking tunnels deep beneath the planet carved out by previous generations of mining. However after nearly one-hundred years of trying to remove the Xenos the Imperial Authorities went ahead with establishing a colonies beneath the planets surface in the ruins of the Halarume's former homes. Content with putting up with small and increasingly disorganized guerilla attacks the moons first human colonists arrived in 001.M31.
It was during this time that the first planetary governors commissioned the Mechanicum for its now infamous mining equipment, survival suits and giant rigs used for excavation down on Oblivion.
Despite how recently the new colony had been established the planet was relatively untouched by the immediate outset of the Horus Heresy, with the planets relative youth leaving it strategically insignificant due to a poor infrastructure. However the world did support the loyalists during the civil War, supplying a large number of colonist to the Imperial Guard to help in the war effort.
It was not until the Great Scouring in 019.M31 that the planet saw any direct action, with a small splinter group of the Night Lords attacking and occupying the planet and attempted to subjugate the population through fear, and aimed to exploit Oblivions vast mineral wealth. This however did not go as plan as the relative handful of fifty Night Lords found a population who where not afraid of the dark. The weapon that the Night Lords that had long considered their ally was rendered useless by a population who spent much of their time in near total darkness away from their homes. Moreover the traitors disregard for the local population and the vengeance they reaped on the loyalists in an attempt to pacify them led to much of the population arming itself rather than being killed by the marauding Space Marines.
As such the Night Lords met a stiff resistance movement which no amount of slaughter seemed to halt. The fear they generated among the population had turned against them, with the people of Gemini being more afraid of dying alone and being hunted by the Night Lords then they were of dying in battle. Despite taking horrendous casualties, numbering in the hundreds of thousands, the colonists managed to annihilate all the Night Lords, through a use of improvised military grade mining equipment, open surface tank charges from the remaining PDF, and knowing the tunnel systems better than the so called Lords.
This utter destruction of a invading force through quickly earned the remaining colonists of Gemini praise from the loyalists and as a result received near immediate aid and support, especially from the Mechanicum who were eager to receive their parent Planets vast wealth. However during this assistance the Tech priests attempted to move members of their various military forces onto the planet in an attempt to 'secure' the planet. The response was a near total annihilation of the soldiers moved in, as many of the population had just had to sit through one occupying force and were unwilling to submit themselves to the Mechanicum and were more loyal to the Emperor than the Machine Cult. In most cases the mining colony would have been wiped out, but the strain of the Great Scouring following the Heresy and the need for Oblivions recourses led to the Mechanicum begrudgingly accepting Gemini's independence from them, with it coming under the direct supervision of the Adeptus Administratum like most colony worlds.
However the world has shared a rocky relationship with the Mechanicum since that day, despite it providing recourses to almost two dozen forge worlds throughout the Imperium.
Much of Gemini's history is directly tired to its parent planet of Oblivion, it has a long and prosperous history of exploiting the worlds near endless supply of natural minerals and ores. Even after the-thousand years of mining the planet appears just as profitable as it did to the first human colonists, and with the addition of its vast mining galleys and specialized survival suits it churns out a impressive 0.008% of all Imperial raw materials in its sector alone.
However despite a steady increase in production since M36 the planet has always shared a rocky relationship with the Adeptus Mechanicus due to their attempted occupation in M31. This is in spite of their world supplying 5 major forge worlds and many smaller imperial worlds with the necessary recourses to support their infrastructure. However as a result of their rocky relations the Mechanicus despite having a major presence on the world has frequently tried to undermine the planet's government and has supported at least twelve internal uprisings over the course of its history. All attempts have failed due to the planets stick import laws and powerful PDF outmaneuvering the smaller if better armed forces of the Tech Priests on the world.
In recent years these spats have come to a head especially over the governments decision in M37 to illegally modify its worlds mining suits for military combat to repulse the Mechanicum's latest attempts to overturn the planets government. Under normal circumstances the Astra Millitarum or other Imperial forces would support the Tech Priests in their endeavors. But the planets long standing political stability and importance to the Imperium, in spite of the Tech Priests efforts, have led the Ministorum overturning the Mechanicums plans and allowing these accusations of Tech heresy to slide. However this hasn't stopped the local Forge Worlds petitioning to the Fabricator General himself to launch and interventional fleet, a proposition that is currently under review.
Oblivion's Government is for the most part a Democratically Elected establishment divided into five main divisions to split up the influence one group would have over the other, thus protecting the interests of the citizens by keeping the powers loyal by having the regulating each other. The main groups are the elected members of the Peoples Hall, the hereditary members of the Noble's hall, the selected CEO's of the OHC (Oblivion Harvesting Corporation), the local Imperial Cult leaders and the Planetary governor who is appointed from the general populace by the Adeptus Terra.
The level of power has often shifted between these three factions with the level of control fluctuating due to public support at the time. This is due to the fact each section of the Government (with the noticeable exception of the Ecclesiarchy) oversees its own division of the moons PDF, providing each groups with equipment, training and weapons. This sharing of local military power means that no one faction can forcefully dominate the other, with any arms increases made by one side ultimately leading to the others increasing their own.
This means that the political power on the world ultimately rests in the hands of the people, with them playing the deciding factor in who has the most support through, which is shown in decade spread elections held amongst the entire population.
While in the past there has been corruption and there have been civil war, the ultimate power still remains in the hands of Planetary Governor. While like all his contemporaries he only controls a portion of the planets PDF, he/she has the added bonus of being able to in the Astra Millitarum at any moment of unrest. To regulate this if three of the other four groups feel that the current Governor is incompetent, useless or detrimental to the Planets commitment to the Imperium they can call for his removal. Even so due to political squabbling this has only ever happened three times in Gemini's history.
Oblivion Harvesting Corporation
While all three divisions of the local Imperial Government all play an important role in day to day lives of the people living beneath the surface of Gemini, by far the most influential group is the Government sponsored OHC or Oblivion Harvesting Corporation, which was established in M32.
The company primary concern is using the planets many mining 'Galley' rigs and its massive population to mine the incredible dangerous, but incredible recourse rich Death World of Oblivion. The death rate stands at an ridiculously high and almost inhumane mortality rate of +75%, which is well bellow the acceptable life expectancy for a soldier in the Imperial Guard. However with little else to do with its massive population many of the Humans on the world are forced to work for the OHC in spite of the inherent death sentence that it provides.
The OHC itself oversees the both the planetary tithes and its manufacturing of its local equipment and recourses, with its close ties with the Tech Priests. A relationship which has led to their loyalties being called into question by the Moons population and government. This relationship despite its suspicion has netted the great Hive cities of Gemini not only advance technology, but the ability to maintain its vast mining rigs and powered amour mining exoskeletons.
Its role in the government however is even more complex, as due to its important link to both the Mechanicum and the Adeptus Terra and controlling the life blood of the entire Imperial World, with it often being used as a major political player in local politics. Many powers on the planet from the Peoples Hall, the Lords Hall and even the Ecclesiarchy have used the corporation to advance their own interests on the world by backing its controversial employment policies.
Due to the nature of both worlds environments the people of Gemini are entirely dependent on the Imperium to survive, as the moons thin and wispy atmosphere and Oblivion hot and high gravity nature make near impossible to grow food. Excluding many protein and vitamin vats held deep in the planets catacombs.
However they alone cannot support the worlds massive and constantly fluctuating population, meaning that ships arrive on a near weekly basis to keep the population fed and happy.
The planet itself exports an impressive 0.008% of all of its sectors recourses, with its output often being sent to nearby forge world. With its sheer amount of recourses making many of these super factories almost entirely dependent on Oblivion and by extension the OHC to keep them supplied and the material flowing.
Interestingly classified Imperial records have shown that the Callidus Assassin maintains a Temple on Gemini under the classification of manufacturing and archeology.