It was noted that, in ancient times, most of the Forerunner Alliance separated, taking their people through interdimensional portals to other universes, leaving only the Sobv'h to remain in the universe. However, this separation caused many of the races' downfall: the Aesdherians were exterminated by the Hikarans, who were later destroyed by the Shivans; the Forerunners literally blasted the Alteran individuals that came with them to the stone age, before wiping themselves out, leaving the devolved Alterans alone; the Iconians were annihilated, and the Hubrin locked themselves away in an anomoly with their mortal enemies, the Metar. Only the Sobv'h, who stayed behind, and the group who followed the Vorlons and Shadows survived.
Recently, however, members of some of the races (or at least examples of those races' tech) were returned to this universe over the years, including Iconian Technology and Hubrin individuals who were freed from their imprisonment. Furthermore, the surviving Forerunner constructs are selecting Reclaimers and Inheritors, giving the Forerunners a new foothold in this universe.
Members of Alliance RacesEdit
These include, but are not limited to, Forerunner Inheritors and Vorlon-affiliated Telepaths.