B'ra'Sha civil war

The B'ra'Sha civil war was a major interstellar war between the Kau Nation and the Dru, Reh and Mai Nations of the B'ra'Sha people that drastically reshaped the space of their society and ultimately had a major influence on galactic politics for centuries to come.
It started with several warlike leaders coming to power in the Kau Nation and attacking colonies of other nations in several different stars system.
Unprepared the other nations were on the back foot against the traditionally militant Kau, and in their desperation had no choice but to put aside old differences and work together for the first time.
Over several years, and after billions of deaths, the Kau were defeated by the new alliance and they were banished from Paplin forever. They left in what became known as the Grand Exile.
The fallout of the war was that it formed a unified central B'ra'Sha government for the first time, and exiled the Kau Nation, who woudl go on to reforge themselves as the Ra'Shain and found the Ra'Shain Federation.