Expanse History
A long time ago a group of refugees left the oppressive, technologically stagnant earth and followed a trail of alien ruins across the galaxy. The pilgrims called these ancient beings Angels. Some said that the Angels where divine beings, and by finding out what they knew, by ultimately becoming them, humans could ascend as they had done. Wisdom, said the believers, would come from studying the ancient works of the Angels. These would become the Black Rose.
Others believed that the Angels might not be divine but where instead simply a message from the universe: That technology did not need to stagnate. If enough augmentation was done to a human being, they too could reach the heights that the Angels had climbed. This group became the White Flame.
On the long trip the factions where separated. Both however managed to reach the promised land: a paradise filled with pleasant habitable planets, many far richer and easier to live on than earth. Few sapient races lived within the realm, and both sides settled down and began to build. The two philosophies did not adopt direct rule, and various countries and power groups developed within their territory. The two factions remained the strongest however.
Problems where encountered. The White Flame's end of paradise had long been used as a fallow resting place by alien nomads, and abutted several powerful alien empires. Several of these alien powers objected to the presence of the humans in their aeons old land. Some of those where willing to use their power to expel them. Unwilling to be expelled, the pilgrims fought.
The Black Rose had no problems with external invasion, but several internal ones. The decision to base most colonies around the major works of the Angels caused geographic rifts to develop. While the Black Rose's leadership sought to apply central control they found it increasingly difficult to keep leadership of their far flung enclaves.
Further rifts developed over how best to pursue the goal of becoming the Angels. Even surrounded by their works information on precisely what the Angels had been and believed was maddeningly hard to understand. Some suggested that they should modify themselves extensively towards a form more like what little information could be gleaned, while others worried that this might take them further from the state of grace they sought.
Finally there was the issue of uplift. Many in the Black Rose believed that the help of alien beings, including some who had joined them during the trip would offer new insight into the Angels. Evidence that the Angels had also uplifted other races added theological impetus to this practices and states and factions began to make it their primary activity. Major disagreements developed over whether non-sapient creatures should be uplifted, or whether human DNA should be used in the uplift process began to develop however, resulting in more bad blood.
In several cases these factional rifts developed into open conflict.
The White Flame was not without factional issues. The mainstream accepted the creation of AIs and major genetic modifications, including some sourced from other creatures, providing they kept the human mind. Factions developed who denied this doctrine, and they quickly gained the support of several powers that wished to escape the White Flame's central authority. For the first time humans warred with other humans in the White Flame area of the Expanse.
The battle might have been much worse if it hadn't been for another alien migration. An alien race called the Centipedes by humans, perhaps following the trail of the Angels much in the same way humans had arrived in the area in strength. While initially the White Flame welcomed their conflict with other alien powers who had long been their antagonists it seemed that the Centipedes would not be content unless the whole area was conquered. The new arrivals advanced technology allowed them to conquer many human worlds, and forced both White Flame factions to end their dispute and stand together against the threat. Over the next hundred years the White Flame checked the Centipedes advance and drove them back, retaking those worlds they'd taken and finally pushed them out of the Expanse, then mounting a series of expeditions which conquered the Centipedes bases beyond its borders.
It was here they encountered the Cacophony for the first time. These creatures, by far the most alien humans had ever encountered, seemed to have myriad forms and shapes, but produced a vast Cacophony of signals around their worlds. These signals had previously been detected but it was only now that humanity met them in the flesh. The Cacophony had apparently been engaged in fighting the Cicadas themselves, demonstrating an incredible but very strange technological mastery. Further they where perhaps the biggest alien empire yet encountered, fully equal to the size of the entire White Flame settled territories. Efforts to communicate proved fruitless, even basic mathematical concepts where subject to disagreement.
Worse the Cacophony's creation of Namari, a race of beings apparently identical to humans. The Cacophony settled them on their own planets and then left, leaving the Namari various devices and items including machines taken from the Expanse. Their motives, as ever where completely known. Worse, the appearance of the Namari threatened to reopen the factional split between the various White Flame factions. The Purists believing them to be an abomination and wanting nothing to do with them, while the White Flame's central organization believed the humanitarian consequences of isolating the Namari to be too severe. Even without the Namari the White Flame now had numerous planets of conquered aliens, and the question of how exactly to deal with them.
As the White Flame was digesting its conquests and attempting to deal with their new citizens, the Black Rose had their own alien problems. Victims of an eons old calamity, the Sea Devils had hidden deep in vast survival bunkers in the crust of various planetary cores. Some would in fact emerge in the White Flame zone, but they proved more troublesome for the Black Rose. Ancient and proud beings the Sea Devils seemed unwilling to undergo the uplift practices the Black Rose usually deployed, and with their buried weapon caches, held the means to turn their resistance into violence.
Apostasy was spreading as well. The discovery of a large set of megastructures built by beings other than the Angels catalyzed a new religious movement which saw the megastructure builders, not the Angels, as those to be emulated. While the Black Rose was quick to point out that the builders where far simpler than the Angels, the New Builders as they called themselves had the advantage of access to ancient builder technology and doctrine they could easily understand.
Finally, ten years ago, the two halves of the Expanse met. With communications established there was a rush to claim the planets in between the two, accelerating the merging. Different ideologies led to conflict. On both sides dissatisfied groups looked across the new border for possible allies. A new cold war of espionage and build up began along the interface, with some states finding their loyalties divided by waves of newly popular religion flowing from the other group.
Worse the Paradise sector is almost fully. The way coreward is blocked by the Cacophony, while Edgward the stars begin to thin out towards the edges of the galaxy. To both sides there's fewer habitable worlds, and many require extensive terraforming.
It's not a bad time for everyone though. Traders and adventurers see great opportunity in the untapped resources of the other side. Projects that would never previously have gained resources are now see extensive investment if they offer prestige or new possibilities. Cultural trade across the line offers the possibilities of a new renaissance of art and technology.
Some even suggest that it is time to expand beyond the promised land. To retrace the steps of the ancient Pilgrims and discover what befell the rest of the human race.