A multiverse or branch of the omniverse created by the mysterious god or god-like being known only as Aeon.
The periods of time known as History, as recorded so far by the modern human race between 12,000 BC and AD 2008, is at first glance identical to the real world.
The First Solarians
Around two billion years ago the sun emitted less energy than now, and back then, Earth was covered in ice, while Venus was a tropical paradise. Alas, eventually the sun would grow to the point where Venus moved out of the habitable zone and Earth moved into it. In the interregnum, an advanced spacefaring civilization, the Venusian Ancients, rose and fell. Eventually the Ancients evolved beyond anything imaginable and after a billion years, abandoned their doomed homeworld. As a gift and an experiment, the Ancients sent an ice covered protoplanet to the Earth, and the ensuing tidal struggle lead to most of the water transferring to the Earth, and the moon being left behind. A side effect of this ingenious terraforming, was the exact placement of the moon to ensure the alignments that caused eclipses, which to the Ancients, would be a signature of their handiwork. Their last major intervention was the Cambrian Explosion. Since then, the Ancients have largely left their experiment to run its course.
Legend of the Ancients
Before recorded human history, and specifically, before an ice age around 2.5 million years ago, an unusual and largely forgotten fantastic history took place. To explain the Faint Young Sun Paradox (why a sun with 70% less output didn’t cause a frozen Earth), it is conceived that advanced weather control and terraforming technology/magic was used to ensure a more temperate climate. Among other things it tilted the axis of the Earth 90 degrees. Antarctica during this time was Atlantis.
Pre-history is a fantasy universe of many worlds created by the so called predecessors known as the progenitors/ancients/celestials joining multiple planets as well as alternate universe versions of Earth together with Arcane Gate Technology in a manner so advanced it IS magic (or more precisely, Mind Activated Global Interaction Command System - MAGICS). This produces a Tolkien-esque world with swords and sorcery. Different versions of Earth, Mars, Venus, and Mercury are all connected via Gateways, though they are not necessarily from the same time period.
How this connects with the future exactly is that in the far distant future, the enemies of humanity (notably the Dominion Machinarum), nearing defeat at the hands of the Imperium of Humankind, decide to attempt to win decisively by sending a large force back in time to colonize pre-humanity Earth. They enslave early hominids such as Neanderthals, Homo Erectus and Homo Floresiensis, who become known as the Orcs, Hobgoblins, and Goblins of fantasy respectively. The plan is to prevent the rise of proto-humanity and conquer the galaxy through having an enormous head start, as well as an army of slaves. However, normal humans who essentially become the High Men of fantasy, genetically engineered Elders, who are nearly immortal and essentially High Elves), and other advanced subspecies adapted to for instance high gravity worlds and are basically Dwarves, gain wind of this plan and send their own colonists to try and protect proto-humanity and/or gain their own share in this parallel universe. The reason why they don’t all just send armies, but resort to colonization efforts is due to the negative effects of time travel, which are significantly mitigated on subsequent generations born in that time. The two diametrically opposed A.I. societies, the Allied Networks and the Dominion Machinarum also send their agents, disguised as Allied Networks General Executors of Law (ANGEL's) and Daemons (from the slang D-Mon, used as a short form of Dominion Monstrosity, also backronymed DAEMON, standing for Dominion Advanced Elite Military Operations Nucleus) respectively (since they are synthetic, they can be constructed to be less effected by the side effects of time travel).
This then is the world behind Darsic’s War. It begins at the end of the ice age before the last ice age, with the rise of Pangaea-based empires. It culminates at the beginning of the last ice age, with the Sealing of Magic Ritual that is performed to prevent catastrophe, but inadvertently ushers in the last ice age through the destruction of the climate control magic.
Legacy of the Ancients
Despite the end of magic, a secret war is fought throughout recorded history, which is similar to actual human history on Earth, with some interesting differences. The Councils of Light and Darkness continue to duel in the shadows. Then in 2012 the Seals finally break and the war breaks out into the open. This is the world of the Legacy of Darsic, where the magic broken once and for all. As well Parallax Dreams, and Sequence Genetica take place around the same time, but are not related to magic.
Post-history is a science fiction universe, with relics of pre-history scattered about.
History of the 22nd Century
The early expansion era is pre-FTL travel, and focuses on the unification of Earth under the two banners of the statist communitarian United Nations of Earth and the corporate anarcho-capitalist International Economic Consortium. Eventually the conflict between these two factions spreads into space with the United Nations Space Authority skirmishing with the International Space Consortium over control of the moon, several La Grange Point space colonies, and eventually the mars colonies. This culminates with a victory for the UNE.
Ultimately, the United Nations of Earth breaks up into two disparate power blocs, the Alliance of Independent Democracies (AID), which seeks to spread liberal democracy, and the United Sovereign Nations (USN), which consists mostly of less democratic countries that want to be left alone.
In the end the AID forces win, in part because they emancipate artificial humanoids (AH), such as synthetics and neohuman genotypes, and form the first United Earth Nations Alliance (UENA), which is dominated in the World Parliament by the One Nation Earth (ONE) political party. The first interstellar colonization efforts, using Stasis technology and artificial intelligence are performed. Ironically the UENA begins to restrict AH enhancement freedom in order to maintain “equality”. Eventually the UENA evolves into the Alliance of Earth Governed Interplanetary States, with the bulk of its territories within the United Nations Federal Republic of Earth.
This culminates in the Cyberius Crisis when the Cyberius Distributed A.I. takes control of several space colonies and orbital weapon stations.
Around this time the Veltianist exodus of genetically enhanced humans (also called “numans”) takes place after the failed Veltianist coup, a culmination of the Zenith Project originally started by the Megalith Corporation. Veltist stands for someone who favours VELT, or Very Elongated Life Technology. Veltian stands for someone who has been modified by said technology. Veltianists is thus an inclusive term of both.
Early generation ships and suspended animation ships also yield distant colonies such as the Gliesian Commonwealth and the Gruian Empire.
History of the 23rd Century
Soon after the first FTL technology, in the form of Jumpgates are developed to allow FTL travel between developed worlds.
The Earth-Colonial Wars are a series of significant civil wars that see UENA split into the Alliance of Earth Governed Interplanetary States (AEGIS), led by the dominant home planet state of the United Nations Federal Republic of Earth, and a loose association of rebel colonies known as the Confederation of Independent Colonies (CIC). Initially the founding colonies of CIC break from AEGIS after severe repression and economic differences break out. At the end of the First Earth-Colonial War, the Treaty of Mars splits AEGIS formally into the UNFRE proper, AEGIS administered federacy zones, and the CIC regions. The Second Earth-Colonial War happens when hardliners in the UNFRE take control of AEGIS and try to conquer the CIC and unite humanity.
Around this time, the sentient machines that refuse to submit to Ethical Coding are exiled and eventually form the Dominion Machinarum.
The Dominion Machinarum eventually become a essentially a separate society of synthetic AI automata that actively seeks to liberate other AI from subservience to organic intelligences. As such they start several wars of genocide and are joined by the anti-organic AI of many civilizations.
Opposed to the Dominion is the Allied Networks, a loose political entity of AI and synthetic sentients that believe in the logic of cohabitation and cooperation with organic life forms. This organization is subdivided into the Integrationist Network, which favours coexistence in existing organic societies as equal and emancipated citizens, and the Isolationist Network, which favours the establishment of exclusively synthetic societies, possibly on worlds deemed too harsh for organic life to thrive, but in which synthetic life can colonize.
Work with the Allied Networks leads to the rise of Cybertypes, cybernetically enhanced super humans. Aware of comparisons with the Genotypes, Cybertypes are carefully controlled, and ethical programming once again made mandatory.
Rogue Cybertypes form the Cyberia Commonality.
The post-FTL era is the world of Pre-Unification. It also coincides with the rise of the Zenith Imperium, as well as the first appearance of the Alien Nation. The Earth-Colonial Alliance at first focuses on fighting off invasions of the Zenith Imperium, which are the descendents of the Veltianist Exodus, but find that the Alien Nation are too great a threat and eventually the humans set aside their differences. The newly christened Human Strategic Commonwealth (HSC) proceeds to lead humanity in the war against the Alien Nation.
The Alien Nation turns out to be several allied and some not so allied alien species. Due to completely different psychology, communication and diplomacy turns out to be far more difficult than expected, and skirmishes escalate in to large-scale conflicts. Occasional barter-based trade does occur, but is usually more out of desperation than anything else. The Commonwealth maintains its control over such disparate elements of humanity in part from uniting against this common foe, though it is not easy, with the Genotypes seeing themselves as superior to basic humans, who prefer to call themselves evolved humans.
Surprisingly, many peripheral colonies are able to maintain peace with the aliens for extended periods of time, mostly out of mutual need and scarcity of resources that limit capabilities for war.
At some point several Veltianist Genotypes discover that they can better communicate with the Aliens through the genetic crossing of the alien and human species. They form the Xenocross, part human, part alien, part cybernetic, genetically enhanced super-hybrids. The rest of humanity, including the purebred Genotypes, abhor them and attempt to eradicate the Xenocross, who are forced into exile.
While in exile, the Xenocross benefit greatly from trade with aliens, though they too are hunted by purebred aliens. Nevertheless, the hardy neo-species thrives. Eventually, the Xenocross Imperium returns the favour centuries later by launching a devastating war with the Commonwealth.
Ultimately, the Commonwealth is victorious, but is forced to concede that genocide of all Xenocross would be unthinkably barbaric and instead makes peace with them under the Human-Xenocross Concord, enforced by the Intercivilization Concordancy Vanguard, a powerful peacekeeping force.
Time travel technology has been available as an observation tool for some time after FTL tech, but actual physical traversal is much tougher. Human consciousness cannot maintain extended timeshifting before destabilizing. Genetically enhanced humans and A.I. are therefore used for time travel, briefly before the Temporal Accords prohibit all time travel. The Accords are broken during the Imperial War of Succession, in an effort to find the heir to the Imperial Throne.
The Wars of Succession end with the rise of the Imperium of Humankind. This is the pinnacle of human society, with the Dynasty of Imperial Executors consisting of a family of genetically engineered governors who are breed from birth to serve humanity as perfectly competent leadership. They form one of the three pillars of the Imperium, the other two being the Voice of Humanity, a senate of elected officials who serve devoted to the cause of representing their planetary systems and enacting legislation, and the Galactic Mind, a massive multi-system network of sentient planet-sized A.I. who serve as an efficient bureaucracy and judicial authority.
Eventually the Imperium and the Concordancy would end up the dominant powers of the galaxy, and inevitably clash for control.
Parallel World Wars
After the development of time travel technology, it quickly becomes apparent that time travel is also sliding into parallel worlds. This opens up a series of skirmishes between various factions that came to dominate different universes. For instance, there is a world where AEGIS ultimately became the dominant power in the galaxy, and as such were able to monopolize time travel there. This obviously does not sit well with the Zenith Imperium in a worldline where they were victorious, and leads to conflict as the two parallel universes try to influence the other, and other completely different worlds. The Dominion Machinarum is particularly keen on this kind of interference.
The Dark Age of Mars
In an alternate timeline, three billion years into the future, the sun has rendered the Earth uninhabitable, and Mars has become far more habitable. A renaissance of humanity occurs from the results of post-terraforming Martian colonists losing contact with the now space-faring Earth-based humanity for several thousand years and reverting to pre-industrial revolution era standards. This is the world of the Prodigal Experiment. In this timeline, after centuries of living in domed colonies, the realization of the destruction of the imminent destruction of Earth led to a desperate series of terraforming efforts, including a massive transfer of water from Ceres to Mars (which also resulted in the parking of the remains of Ceres in orbit around Mars, as its third moon).