There is a legend from the end of the Bastard War. As the singularity arks of the Obelisk Dreamers fell one by one, they became desperate. Hoping to recreate one of their lost vessels, they took one of their planets and wired the minds of the servitors on it together, creating a planetary super consciousness . Then they killed the entire planet in " a wave of death". The aim was to use the pain and anguish of the dying super consciousness to pierce a hole in reality in order to build a new ark. As the story goes, the plan was an apparent success; the death scream of the planet created a new singularity. From here, the story diverges. In some versions, the colonists of this new ark were driven mad by the spirits of those they killed to create their new world. With their sanity gone, they mutated spiritually and physically into hideous new forms, the infamous ministers of the Undersphere. In other versions the ministers were already born there when the colonists came, ready to inflict karmic horrors for their sins.
The truth of these events may never be known, and indeed there are many who believe none of it ever happened. Neither the less, the undersphere and its ministers are real. They are a problem for the rational and the skeptical. They seem to be creatures of myth and superstition given form, dark gods from the legends of a less enlightened age. It is believed that they use some form of psychic power to achieve their various gruesome miracles. This is ultimately correct; the ministers feed off of psychic energy, particularly fear and worship. The belief that they are gods fuels them. This perverse incentive makes the ministers showy and dangerous. They are ever eager to impress and horrify, seeking to cultivate a captive following that they may feed on.
As spooky as they are, the ministers would be nothing but a backwater horror show without the reborn. They are ordinary sophonts that have been remade into creatures from the dark corners of the imagination. They serve as the Ministers agents and soldiers in the galaxy, and together they have carved out a chunk of space where the borders between fiction and reality are blurred. Known formerly as the Undersphere Reaches, and casually called the Undersphere, this region is wracked by a constant low scale civil war. The Ministers seem almost congenitally incapable of working together, betraying and sabotaging each other like catty office workers. The space navies of the Reborn are mostly used for piracy; sometimes against outsiders, mostly against each other. Though the Undersphere might seem like easy picking, at the first sign of a common enemy the Ministers unite. They relish war, and have vast arsenals of terror weapons that make fighting them a hellish experience
The Reborn are a diverse lot, seemingly culled from the mythologies of dozens of disparate cultures. The key commonality is the concept of transformation; they were born "mortal", and were "reborn" into their new mythic forms. Every transformation begins with an infection vector of some kind, be it bite, sting or intravenous injection. Not every transformation results in a viable Reborn; those that resist or doubt the reality of the Reborn often end up as non-sapient monsters.
Reborn absolutely buy into their own mythology. Aside from how the transformation process favors those that believe in the supernatural, there is a culture of "spookiness" among the reborn. Having a "haunted" lair, owing a lot of "occult" artifacts, or having mythic creatures as minions are all signs of status. There's more to this than simple pageantry; the Ministers prize aesthetics as much as competency. Success and prestige can hinge on having the best collection of creepy skulls.
There are dozens of minor clades of Reborn, but three major families. Theoretically, any sapient could be reborn into any family, but cultural background is a big component in whether or not a transformation is successful. Every transformation is highly idiosyncratic,
Vampires are an old human myth about diseased corpses returning to life to drink blood. Reborn vampires associate themselves with blood, death, feral animals and dangerous sex appeal. Physically, vampirism is marked by pale skin, bestial features and extreme dentition. They are commonly either extremely gaunt or massively corpulent. They can poses incredible strength, speed, regeneration, senses and hypnotic powers. Culturally, Reborn vampires have a strong cult of exceptionalism. This leads to a certain vampire chauvinism that colors their relation with other Reborn. They are famously vain and have a studied confidence about them. A vampire at rest lounges. A vampire in motion prowls.
The Deep Flesh come from an Agredeem legend about the baleful creatures that live in abyssal oceans. They see themselves as secretive and subversive. According to legend, the Deep Flesh kidnap and replace people with uncanny doppelgangers. When the Deep Flesh Reborn induct people into their ranks, they convince them that they were always a sleeper agent and that they are awakening to their true selves. This requires no small amount of brainwashing. The transformation brings hyper flexibility and mailability of features. Many grow chromatophores on their skin that they use for disguise and camouflage. Some develop bioluminescence, which is seen as a sign of great spiritual power. They all have a sort of predatory empathy, and many have deadly venom. If they couldn't breathe underwater before, they can now, but they need to keep their skin moist and they can have a fishy odor. Among the Reborn they serve as spies and assassins, though there is a niggling paranoia that their actions ultimately serve their own agenda. This feeling is deliberately nurtured by the Deep Flesh.
The origins of the Insiders are murky. Similar creatures appear in the folklore of most exoskeleton bearing sophonts, and also in the popular media of some soft bodied cultures. They seem to have been inspired by the fear of parasitoids. Insiders are insectile monsters that lay their eggs inside other living Sapients. Their transformation is the most fraught of the Reborn. The prospective insider must identify with the life growing inside them. In a deliberate act of will they must transfer their self-image to the parasitoid. If done correctly, the creature that emerges will be fully sapient with the hosts memories and personality (at least as much personality that can survive being transformed into a giant bug). Insiders are strong and quick as a rule, and many have amour-like exoskeletons. Beyond that, they can have a dizzying array of chemical weapons, including but not limited to venom, webs and poison gas. Many can fly, a few can burrow at tremendous speed. They have an instinctual command of their non sapient kin. They can be just as chauvinist as vampires, but while the bloodsuckers are haughty and dismissive, Insiders are smug and condescending. They are found of extolling the virtues of insects and vermin, though they loathe the church of the Holy Vermin as a rule (bugs should feast on mortals, not the other way around). Most Insiders take a perverse joy in being gentle and polite to guests and captives, as they know they can always make things incredibly nasty later.
The Undercatherdral of Pale Corpses is one of the gargantuan space ships that roam the Undersphere Reach. It is notable because it is filled with a half rotting, half regrowing corpse of some forgotten godling. The engineered flesh is constantly seeking to reform, but its thwarted by teams of slaves hacking it into pieces and harvesting the interesting bits. These bits are then taken by one of the Reborn fleshcrafters and fashioned into frankenstiod monsters*. This cathedral is the permeant home of Minister Gelwar. He appears as a massive stitched together corpse with a solemn gold face mask. He spends most of his time inside a massive pile of bodies, only emerging to make demands of his followers.
The Deep Dark Wood has a biosphere custom engineered for the Reborn's aesthetic tastes. It is a resort world where the upper crust of the Reborn come to relax in twisted, primeval forests. There is little civilization here, only isolated hunting lodges. There are plenty of jobs for hunters and guides, but check the contract to make sure you're not joining the hunt as a quarry. The planet is home to Minister Tiranp, who takes the form of a giant winged face made out of vegetation that is constantly leaking maggots out of the eyes and mouth.
Undersphere city is a titanic space station teetering at the edge of the undersphere itself. This close to the singularity, space is warped in weird ways**. The city is an impossible labyrinth of narrow streets and blocky buildings. Though most districts are run down, there are more people living here than you would expect. When the wan electric lights are on, its safe enough. People mill about like any other city. However, there are rolling brownouts that roam around like living things. When the lights flicker and die the locals scramble for shelter. The lucky ones close their blinds and ignore the screams.
Dr. Gulmor is the head of the team of Fleshcrafters working in the UnderCatherdral of Pale Corpses. She is a long centipede-like Insider. Her position affords her a great deal of power and privilege, but she is well aware that any of her underlings would gladly betray her. This is why she pits them against each other in high stakes practical tests of their work I.E constant monster battles. She collects corpses, and will pay well for any unusual specimens.
Count Garlach is eccentric even by Vampire standers. They are quite wealthy and own most of the Deep Dark Woods' western hemisphere. Their lair is a sprawling manor deep in a trackless wood. They pay foreigners from all over the Galaxy to attend their overnight dinner parties. The catch is they collect various psychic predators and let them roam their house freely. Survivors are awarded bonuses based on how many rooms they explored and how many times they mated with other guests, which is tracked through mandatory implants.
Isligtar is the head of the scavenger's guild of Undersphere City. There are many forgotten and crumbling districts in the city, and there is money to be made picking over their corpses. This is only the first layer of his business model. When a scavenging team goes missing, he sends in a retrieval team to capture whatever took them out. He has a warehouse full of urban stalkers and cursed objects he sells off to other Reborn. He is of the Deep Flesh, though he is careful to never use any of his powers while he is wearing his business face, keeping the full extent of his abilities concealed. He has a moist sheen to his skin, and large, watery eyes.
*The Undersphere Reaches can be said to have a monster based economy, with the various factions struggling to control the means of destruction.
** The Undersphere isn't a standard model black hole, so this warping isn't the kind predicted by general relativity and there is no noticeable time dilation. Shut up nerds.