Nulvar is the planet that Mastal, Trivas, and Jorell first went to after being exiled from the Chiss Ascendancy. The native Nulvarl quickly embraced the Dark Jedi and their Chiss allies. From there, many other planets joined them to gain access to the more advanced Chiss technology. Soon, the Nulvarl Empire was created.
When Trivas and Jorell overthrew and killed Mastal, they kept joint command of the Empire. Slowly, through political manipulation and military conquest, they added more planets to the Empire. Soon, they gained the attention of their neighbors who decided to do something about the aggressive Nulvarl. They formed the Areltsi Coalition headed by the planet Areltsi which declared war. While Nulvarl escaped most of the damage, it saw minor destruction when Jorell betrayed Trivas and slaughtered those loyal to him.
When Jorell declared war on the Ni'novian Empire, he was defeated. The results were that Nulvarl was attacked and a series of roving battles took place on its surface. The losses would have been worse except that many of Trivas' old loyalists took out key positions of their enemies and captured thousands without a shot. The planet surrendered after only three days of fighting and became part of the new Nymean Ascendancy.
Things settled down after the change of government. While the Nulvarl send more than their fair share of troops to join the Nymean Ascendancy, they have restrained their aggression. Some of the older Nulvarl miss their years of dominance, but most have accepted that Areltsi would now be the capital of their old empire.