At the end of the Second Galactic War, the scattered remnants of humanity were led to the Core Worlds by the Lacir.
This became known as The Great Confluence. What remained of humanity settled across the seven planets of the Demetus Cluster.
With no way to maintain or rebuild their existing technology. Humans regressed to pre-industrial and agrarian societies. Efforts were made to reverse engineer the technology lying in ruin around them, but some groups preferred to forego their past and live a simpler life.
Thousands of colonies across the galaxy were left entirely or partially behind. Many were destroyed by Morocaschic remnants, others failed due to lack of inter-system trade. A few survived through the coming centuries and were forcefully rejoined with humanity during the Consolidation Wars.