The great war of the nine
From ROI Wiki
Not much is known about the Great War of the Nine Races other than it unfolded nearly two millennia before the events of The Oort Perimeter, and was instrumental in, not only the extinction of 6 of the original 15 "ancient races", but also played a large part in the forming of the UGW, which stood as a powerful bastion of peace in the galaxy for much of that same period of time. It also led to the unofficial formation of The Nine Ancient Races, as well as the galaxy as it exists at the time of First Dawn.
