Warning: the following planet takes some liberties with astrophysics. I am not an orbital mechanic.
Two inhabited planets circle the star of Mandrobaum. One is dying, the other is being born into a cruel inheritance. Mandrobaum II, once a centre of learning, culture and enlightenment without an equal in the sector, lies desolate, its only remaining inhabitants the abandoned dregs of society. Those who have not resigned themselves to their fate are increasingly desperate to escape their fate on the doomed planet. The moons of gas giant Mandrobaum III bristle with the adamantine skeletons of new construction; each of the three icy rocks is on its way to becoming a fledgling hive world.
Mandrobaum has been a leading light in the culture of Belsegoria for as long as can be remembered, producing artists, scholars and gentleman-warriors from its universitat and sending them out amongst the stars to make known the name of their homeworld. But this world is no longer a green and leafy oasis against the backdrop of war - Mandrobaum II has entered its final days.
This crisis has been in the making for six thousand years. Long ago, during the reign of Arian the Mystagogue, Mandobaum was held under the vicious rule of the Immolatrix, a dangerously intelligent devotee of the Blood God. She pillaged the libraries and set a thousand fires in the cities, brutalising the people of Mandrobaum for decades. It eventually became evident, of course, that Lady Militant Belsymia’s crusade of reconquest would be victorious.
Her orbital support lost and her armies exhausted, the Immolatrix made her final act of defiance. She detonated the world’s entire nuclear and conventional stockpile simultaneously, all in one small section of the western continent. The rest of the reconquest had to be carried out by Mechanicus heavy skitarri and helmeted Astartes, such was the fallout cloud covering most of the planet, but it was reconquered.
Centuries of time, aided by the ingenuity of the surviving intellectual elite of Mandrobaum, healed the world. This slow recovery, however, gave way to deep sense of unease. The system’s astrographic charts were wrong. It slowly became apparent that Mandrobaum II had been dislodged from its orbit and was slowly, painfully slowly, spiralling towards its own sun.
None of the generation which made that discovery has lived for two millennia, but over time the question of what Mandrobaum II’s population should do has become increasingly urgent. Recent decades have seen successive planetary governors seek to broker resettlement deals with their peers elsewhere in Belsegoria, but the high demands made by the governors have always prevented a final deal being reached. Slowly, the intellectual and economic elite have trickled away, to their planet’s old rival, Jotunheim, or elsewhere. All that remains are the lower classes - literate, yes, but unremarkable.
The final governor, Chancellor Horsca, has made a deal which serves his own interests - the Administratum will pay for the construction of three new hives on the moons of Mandrobaum III, and Horsca will supply his own people to serve in them. They will be indentured data entry clerks in a new hub of the Imperium’s bureaucracy. Horsca, of course, will be the new planetary governor, his quality of life undiminished.
Mandrobaum II
The old world is finished. Almost everything of value is gone, the libraries have been sold, destroyed or taken by the Administratum, the cities have been stripped of their valuable goods and all sources of civil order have withdrawn. Only the dregs, those deemed not worth saving, remain, and most of them despair, for there is no escape. Rioting, looting, murder and rape are daily occurrences for those left behind. The only ships which land on the surface now are illicit salvagers, taking the last pickings before the parched world tips into its final dive.
There is one prophet of hope, proclaiming a miracle to come, She Who Speaks of Light. The Imperial authorities, having abandoned the world to its fate, do not know of her, but everyone on Mandrobaum II knows who she is, and some hope she is their prayed for Messiah.
Mandrobaum Orbital
Prefabricated in the great docks at Syzygy, Mandrobaum Orbital hangs outside the orbit of Mandrobaum III’s three natural satellites. When finished, it is intended that it should serve as the administrative hub of the world. Chancellor Horsca is already in residence in one of the finished portions, as is Adept Gawain Atremius, his liaison with the Administratum. The orbital also provides docking facilities and acts as a transport hub. When finished, it will be the part of Mandrobaum most easily accessible to off-world visitors.
Alecto
The hive of Alecto is the only one currently close to operating as the Administratum intends. The hive infrastructure is in place and whilst large portions of the interior remain unfinished it does possess functioning transcription halls and cogitator cores, the first to be in use in the new colony. The population, although certainly discontented, is being kept in line by the Administratum censor teams.
Megaera
Megaera was, until two years ago, almost at as advanced a stage as Alecto, but elements amongst the first settlers have seen to it that its construction has not gone smoothly. A radical group, the Mandrobaum Liberationists, have sworn to force the Administratum out. They are intelligent and ruthless, and have frequently halted construction of Administratum facilities and assassinated high ranking censors and adepts. They seek to find a foothold on Alecto.
Tisiphone
Technical difficulties have slowed the construction of Tisiphone, and large areas of the hive remain without basics such as energy or even life support. Most of the intended population remains idle aboard cramped refugee ships and are growing dangerously restless.