The 38th Century is the Peak of a New Great Era of Mankind. Humanity has struggled through the tribulations of the galaxy, the Secessionist Migrations, the Optimist Incursion, the Slave-God Wars, and most recently the Great Citizenship. But despite all this, the nations of men stand strong, their empires seem stand on feet of granite, and national anthems written long centuries ago echo heartily through alien lungs and jaws. But a darkness begins to dim the glittering hopes of the mighty civilisations of humans, and tensions grow between the mighty empires. Fear and blood and fire linger in the minds of the galactic citizenry but such fears are brushed off as paranoia.
Mankind began its journey to greatness in the 21st century. Their first forays into space were primitive, slow and desperate. Men hailed as heroes in the 38th century, were in their own ages crippled by low gravity and aged prematurely by radiation. But in the latter years of that century, when the Solar colonies were just developing critical mass, faster-than-light engines were developed. Humanity spread across the galaxy with zeal, eager to conquer and exploit the stars and even seek ancient and wondrous alien civilisations. But they discovered something odd. When they found worlds populated by aliens, they found the aliens were primitive, still knapping flints, exterminating megafauna and generally only just existing on the edge of the Stone Age. The United Nations kept these populated yet savage world under protection, but the longer that the great starcruisers travelled, the quicker that humanity realised that while we were not alone, we were not likely to learn any great wonders from the intelligences we encountered. It was also becoming increasingly uneconomical to avoid good, habitable world because there were a few hundred thousand fur clad aliens on its surface.
The first consequences of this, was that while habitable worlds were avoided, sterile planets were enthusiastically exploited, and the fragile craft of the early travellers became extremely robust. Secondly the discovery that the intelligences out there weren't fundamentally more wise than humans crippled a nascent 'United Humanity' movement, and the separate starfaring Great Powers greedily built empires of colossal scale. This caused a wave of nationalism across Earth, and trillions were poured into space programmes, and a state without a smattering of colonies was barely perceived as a state at all. As space travel became ever cheaper, many secessionist groups found that they could find a homeland unavailable to them on Earth beyond the harsh light of the Sun. These groups represented the first Major Crisis, as the increasingly weak United Nations was exploited, and land was expropriated to make way for new colonies. Wars broke out as nations who had worked hard to establish a hermetically sealed colony on an airless moon found it stripped from them and depopulated to make way for a sect of angry Basques. Ultimately, the United Nations collapsed in the face of schisming nationalist groups, and a war was fought across the stars. A great many minority states survived the Secessionist Migrations, and in fact in many ways it strengthened the sense of unity and nationality in many emergent empires like the Spanish Republic, and the Russian Peoples Tsardom.
With homelands like Palaestina established, the new space empires entered an era of peace and prosperity when demands for expansion and resources could be solved by finding virgin worlds to take rather than conflict with one another over borders. A Galactic Ecumene was established to replace the United Nations, and was used to administrate the alien worlds placed under protection. A Prime Directive of non-interference was universally accepted by governments. But individuals and groups found a ludicrously profitable trade in drugs, weapons, slaves and prostitutes could be carried on on primitive worlds. Alien peoples barely out of the Neolithic were easily overawed by ambitious individuals with high technology and on distant worlds could establish themselves as God-Kings. The Ecumene was loath to intervene knowing that intervention would be an admission of failure. But the slavers were ever more open about their operations and the inevitable filtering of interstellar crime gangs from the redoubts on isolated worlds to major colonies of the Great Powers represented a major shift. Alien slaves and prostitutes were found in raids on warehouses across the human colonised galaxy. Deaths from extraterrestrial narcotics leaped and states realised that the Ecumene had failed exactly where the United Nations had failed before it. Military forces were sent to the protected worlds and the Slaver-Gods were rooted out with terrible loss of life. After this, the alien worlds were placed under imperial mandates and were openly exploited.
For several centuries this situation remained stable, though the Optimist Incursion caused a ruckus when the 'United Humanity Movement' was resurrected albeit with a flavour of extreme genocidal human nationalism who blamed the still primitive aliens for humanity's problems. After a series of wars, several empires collapsed and some suffered revolutions, with the Soviet Union entering a second incarnation. After this, efforts were made to educate and improve the lot of the aliens, and from the 24th to the 31st century, a population boom occurred during which some humanity moved from the majority species in most states to a plurality. This was deeply problematic, as humans were used to aliens serving as a visible but not overweening underclass, but the sheer numbers worried them. By the 35th century, humans were a minority in most states, and the increasingly prosperous and well-educated aliens began protesting their inferior status. Many states grew reactionary and put down rebellions with terrible bloodshed. These aliens had grown up under human rule for centuries or even millennia, and in most cases remained loyal to their respective nations but felt little love for the government who ruled them or the elitist upper crust of humans who had grown stupendously wealthy on cheap alien labour.
The Great Citizenship began in the 35th to the 36th century, in which the vast majority of states were forced to grant equal citizenship to aliens. In many cases this was a drawn-out, agonising affair, and in some states isolated on one world, humans still formed a majority and they were safe in their archaic bigotry. From the 36th to the 38th century, the newly enfranchised peoples joined in the work of their nations with renewed vigour, and it is generally agreed that this time since the Great Citizenship represents a Golden Era. But darkness grows in this new era. While states remain dominated by a human elite, aliens are being increasingly co-opted into these circles. For long centuries, peace has been maintained by distracting expansionist ambitions outwards and in a common sense of human brotherhood bolstered by the elimination of secessionist nationalism and the godlike sense of human dominance. Now each state was biologically different from the next in the most bizarre and extreme ways. The British Empire was dominated by the saurian race of the Jeldrahi, while the French Eleventh Republic was mostly ruled by the chitinous scarab-men of Qiqiqiraaqaq. The common sense of human brotherhood was dissolving as humanity became increasingly irrelevant in the governance and life of their nations. And the sheer breadth of the empires meant that outwards expansion was also irrelevant. Conflict was becoming an ever more real and some say certain outcome...