How about this.
During the dark age of Technology, a group of scientists were experiment, questing, searching for a way to achieve immortality. They searched through every means at their disposal, sending out expeditions deep into space, testing the limits of genetic engineering, and even dwelving into the art of nanotechnology. At first, their work was seen as important, and the leaps forward they made into longevity and disease control was hailed as miracles. However, soon enough, the work started to slow, as the limits of their science held back their research. A faction soon emerged amongst the scientists and researchers, one that believed that drastic measures should be taken, and that the ends justify any means. They argued much with the others, and soon began setting up secret labs, and began testing their medecine on patients without consent, even kidnapping the mentally ill, the lower classes and travellers. They continued this for years, and drifted further and further away from morality, but where making good progess, and dark rumours began to abound of missing persons and strange experiments. Soon, the head scientist confronted them, and was murdered. The local authorities immediatly tried to arrest this shadowy group, but the law enforcement officials were killed by monstrous experiments. These desperate scientists then were forced to flee in their research ships and science vessels, as the military came after them. They fled, and were never heard from again......
They travelled far across the void, fleeing from the past. A freakish anomaly in the warp blew them of course, and they ended up in the ghoul stars. Coming across a barely hapitable world, orbiting a dark star, they soon realised that a colony could only be built in the strange network of tunnels and caves their sensors were picking up beneath the planets surface. So they landed, and began to establish a colony in a large cavern. They had already deviated from their original humanity by this point, as a lack of subjects had forced them to experiment on themselves. They now fed on blood, as they had found a way to harvest blood from dead bodies, by using hooking the recently deceased up to machine, which kept certain parts of the body alive, with nanomachines harvesting the non blood producing parts of the body, and feeding it into the bone marrow to create nutricious blood, and solving the problems of food supplies on their journey. These "advanced" humans now had long fangs, greater endurance and the ability to hibernate.
Having established their new colony, they continued their research, and began to increase their population. They no longer depended on sexual reproduction, now being able to reconstitute the dead into a frame of biomass, and then using carefully selected genetic information to grow new adults.
However, they soon encountered a dangerous threat, and the origin of these tunnels. A vicious race soon returned to the same section of the cave systems that the new community was inhabiting, these were the Cythor Fiends. Conflict erupted immediatly, and violently. The former humans, who now called themselves the Nosferatu, after one of their greatest leaders, had the technological advantage, using nanotechnological equipement and weapons, but were much fewer in number. They soon devised a method similar to their new method of reproduction, to reanimate the dead to fight as cannon fodder, and began intensivly enhancing their own physiology for fighting in the dark tunnels and caves. They grew pale, as pigmentation was not needed in a lightless environment, and their eyes gained the ability to see in the dark a if it were day, and they could now sense the heartbeat and bloodflow of their enemies. They gained superhuman strength and speed, incredible hearing, and some bloodlines (as favourable genes were passed down through different factions in the form of "family" bloodlines) now had potent pseudo-psychic power, giving them the ability to mesmerise and sway other people, and in some rare cases the ability to read peoples minds.) and their nanobots, now a fully organic and advanced symbiotic organism which their bodies produced, gave them extremely rapid regenerative abilities, and also made them stronger, faster and more intelligent the older they got, as the organisms continuously enhance their bodies throughout their lives. Aging was now fully eliminated, and their ancient goal of immortality was achieved. The local Cythor fiends, after centuries of fighting, were eventually subjegated, and came to worship the nosferatu as gods, and were used as a source of food, biomass and labour by the nosferatu.
After many, many years, the caves of this planet became full of Cythor fiends (who now no longer fought each other, due to the rule of the nosferatu) and nosferatu. Having become genetically stabilised into their latest forms, the Nosferatu could not change themselves from cave dwellers into forms which could survive the harsh radiation of the surface (or even the solar radiation on most habitable planets of direct sunlight, which now burned them and weakened them). So they came up with a different solution. Instead of adapting themselves, they now built a series of great spires at key points across the planet, using massive amounts of Cythor and "undead" labour. Once completed, the spires were activated. Spewing thousands of nanobots and chemicals into the planets thin atmosphere. Soon, the planet had a dark, thick atmosphere, through which little light or radiation could penetrate. The nosferatu then engineered local cave species, such as small, batlike creatures so that they could survive in this atmosphere, and leave the caves. These creatures would now naturally maintain the atmosphere, excreting the right chemicals, and aiding the atmospheric spires. Now, great cities could spring up across the planet, and the Nosferatu could walk the surface of the planet, and even take nourishment directly from the atmosphere. The billions of bat creatures which now swarmed the sky, would instinctivly live among the great spires, and their corpses would fall into great vats at the bottom of the spires, providing massive amounts of biomass to transform into nourishing fluids. The Nosferatu would now build newer, more advanced weapons and ships, to defend themselves against the cythor fiends from other planets in the ghoul cluster, and to claim their place in the 41st millenium.......
