Records of this period, like all of the ancient past, are fragmented. Much is lost. What is recorded here is but the barest overview of the longest-lasting civilization in all of human history.

While genetic engineering had existed for some time during the Middle and Late Civilized Periods, it had been closely monitored. At best, some old genetic diseases were wiped out, lives lengthened. Certainly inhuman experiments were performed, true deviations from humanity produced, but the stifling regulations of these periods saw such attempts suppressed.

The Solar Empire changed this. In the anarchy of the Late Civilized Era, no power existed to stop them from recklessly experimenting. Their population, desperate for protection and desirous of the benefits promised, if only for their offspring, submitted to the genetic alterations that the ruling class imposed on them. Genetic tampering is no panacea, and the first efforts were crude, but the results were felt. Longevity, health, intelligence were all increased beyond the paltry blessings of their already-changed ancestors. They were not supermen, but certainly they were something new. And as the Empire learned, it tinkered further.

The nature of humanity is not a mystery. Its genetic code is a finite instruction manual that can be understood with sufficient time and effort. While the Solar Empire never obtained godlike mastery over human DNA, it came as close as it possibly could. It learned to tweak inclinations and propensities, to guide individuals towards particular mindsets or vocations. The randomness of life and the effects of nurture ensured that exceptions and deviations would always exist, but for such situations there were other, cruder methods of pruning. These individuals, shaped for particular roles rather than environments, became the Hi-Caste. This population administered to much of the empire, existing as its upper class. Those masses who found themselves dominated by the empire had a less kind fate, but by the time it began its genetic programs the chance to resist in any meaningful way had long since passed. Shaped not for a role, but an environment, the majority of baseline humans became the Lo-Caste, the empire’s common folk.

Ruling over both were the Ur-Caste, the Imperial Clade. Few verifiable records of this group exist, but from what the surviving Hi-Caste speak of, they existed at the apex of biological humanity. With lives spanning centuries and youth that lasted nearly as long, incredibly fit with immaculate metabolisms, and intelligent to a degree beyond any other biological human, all of the empire could be described as a machine that existed to cater to these beings. Certainly, it provided for its people, but it did not exist for them. The empire existed for the imperials, ensuring a perfect paradise for perfected humans, both the land and subjects shaped to their whims. The Hi-Caste, especially, was built to desire their loyalty, mere microexpressions and control pheromones having profound effects on their psyche.

Thus was finalized the Genetic Caste System, the great filter for all human evolution which would come after.

But why do this in the first place? Why reshape humanity when machines could do just as well, if not more?

The Empire was a system of repression, an engine built only to serve its masters. They feared anything they could not control or that which could surpass them. An AI singularity was a danger the long-lived Imperial Clade may well live to see, and so computing technology became highly limited and regulated. Humans would remain the beating heart of space-faring civilization within the Solar System, for humans were something the rulers of the empire were certain they could control and limit.

With their mastery of humanity, they spread across the solar system, but slowly, carefully, and meticulously. Innovation and reckless growth were slowed and regulated. A system of social credit and government aid provided for many, so long as they worked. Even the poorest of registered citizens were guaranteed a meal and a roof, if nothing else. Some even excelled, and were granted the ultimate reward. Their children would be shaped into Hi-Caste, granting their bloodline status and the parents a peaceful and luxurious retirement. Unable to move up in society themselves, this method was the only way for a lower caste to rise in status. By making it generational, the empire ensured that the children of the best and brightest of the Lo-Caste would be born more loyal to their new clade than their original parents. For the most part, it worked.

It was not perfect, however. There were dissidents and the unwanted, revolts boiling up periodically and then brutally dealt with by the war-clade death squads of the empire. Those who lived on the margins and fell through the cracks of the empire’s sprawling administration had no rights or opportunities, living as vagrants or even slaves in isolated parts of the solar system. Constant efforts were taken to wipe out or civilize these lawless pockets, but more always sprung up as others were dealt with.

Technology and the spread of mankind was limited. The solar system was immense, and emphasis was placed on developing it rather than spreading to distant stars. Primarily because so long as all of humanity was in one place, in a single cage, it could be controlled. No FTL communications or travel existed, and a widespread humanity would inevitably become a fractured one which the Solar Empire would not master, so it could not be allowed. Likewise, general AI presented another threat to the Imperial Clade’s power, and so was outlawed as well. Advanced computer programs and self-regulating algorithms proliferated, but none existed without human oversight.

Had N-matter never appeared, this system could have sustained itself for a very, very long time, eclipsing all of human history until the Imperial Clade had utterly crushed dissent from its subjects, and humanity transformed into a eusocial species. Such a fate would have been guaranteed, for while the empire did support the bodies of its citizens, it was poison to the spirit, stamping on self-expression, free will, ambition, and hope in favor of a machine which existed only to sustain itself and those who turned its wheels. That it ended as it did was perhaps the better of the two futures, despite the suffering it would cause.