This is one of a part of setting overviews for the new setting that will accompany the Hammercalled Roleplaying Game, The Legacy of Eight. Its goal is to detail the timeline of the universe and some of the key shaping events.
Earth is venerated by humanity as a holy grail. While nobody in the Saturn Sector has seen it with their own eyes, it is still a major influence, especially in the Empire where Terran styles are more faithfully maintained as part of Imperial culture.
As the tree from which the branches of humanity sprung, Earth is an inauspicious parent. Largely devoid of exceptional phenomena by humanity's later standards, barring the presence of a planet capable of bearing human life and its immediate adjacent creatures without terraforming, it would go on to be the ceremonial capitol of the Immortal Empire and also a powerful politically neutral entity.
There are those who point out that Earth was never free from internecine struggles like some of the galactic civilizations were able to clamp down on after the second Unification. Barring rare exceptions, the world and its immediate neighbors were given sovereignty over their own affairs, and only once in its entire history was Earth subjected to external peacekeeping–and this was achieved by its colonies within its own solar system.
From Earth, humanity would spread to its nearest neighbors. Proxima Centauri was settled by transhumans as the first exosolar colony, and flourished due to the discovery of unexpected resource deposits. While they shunned full machine consciousness, a trend that mainstream human factions would continue, the Centaurans pioneered breakthroughs in digital backup, genetic alteration, and positronic brain technologies that would become standard for later adaptations to exotic planets and permitted true immortality for their citizens.
Back on Earth, conflict and in-system colonization restricted contact with the Centaurans, who would develop their own political and cultural affinity based on Earth's. Meritocratic and capitalist, the Centaurans would launch their first expedition to Barnard's Star, a move intended to show their technological development.
A Mars-backed expedition arrived at the same time as the Centaurans, and the two factions entered a cold war. The Sol system unified to the extent that they agreed to a mutual protection pact and began to assemble the first combat spacecraft capable of functioning as battleships independently patrolling a system, a show of force rather than a practical achievement as small fighter-craft would remain more practical as space combat vehicles until thousands of years later.
The cold war between Terrans and Centaurans would stretch on for centuries. Without the discovery of faster-than-light travel, they were incapable of leaving the stellar neighborhood without risking fracturing. A Centauran colony in the Tau Ceti system was particularly noteworthy for a successful rebellion of extreme transhumanists that would later be quelled by a joint Terran-Centauran force after the Cetans launched attacks against humanity's home systems using drone ships and machine intelligences.
The Cetan extremists launched a one-way colony ship to flee their opponents, and the Terran and Centauran civilizations and their descendants would hear from them for centuries.
In the mean-time, an accord was reached between the two giants. An agreement that would continue uninterrupted for the rest of human history was brokered: the first civilization to reach a system could colonize thirty percent of its planets and planetoids of their choice, and the second could claim their own thirty percent. The remainder were presumed to be left for independent settlements or uninhabitable. At the time, the agreement was simply between the Terrans and Centaurans, but the defining mark of later galactic civilizations would be reaching a point where they could claim membership in the pact.
By the time of the Reunifications, the agreement had shifted from governing individual solar systems to clusters of systems, which had the effect of permitting factions to claim whole systems, which was desirable from logistical, military, and economic standpoints.
Following the Soulscourge, nobody knows what has happened to Earth. Expeditions to the Sol system have been attempted, but none have returned and no sensors or probes have returned any useful information. However, given the general confusion and chaos caused by the cataclysm many scholars believe that Earth is still around, and may merely have been moved from its original position relative to the rest of the universe.