The Mugaari, a humanoid species, were defeated by the Galactic Republic in a swift and one-sided conflict approximately one millennium prior to the Galactic Civil War. As a result of their victory, the Republic forcefully incorporated the eleven planets comprising Mugaari Space along the Corellian Trade Spine, establishing the new Javin sector within the Outer Rim Territories. While the area experienced a subsequent economic boom due to increased trade over the following centuries, the Mugaari harbored resentment towards humans for their intrusion.
One thousand years before the events of the Galactic Civil War, the hyperlane known as the Corellian Trade Spine stretched to the planet of Javin on the border of the Mid Rim, separating the Galactic Republic from what was then considered Wild Space. This frontier region of the galaxy, not completely charted, only drew scouts and the most daring merchants. Javin was part of Mugaari Space, a collection of eleven worlds with some independence, ruled for thousands of years by the humanoid Mugaari, who viewed the Republic with suspicion.
Traders from the region ventured across the Mid Rim frontier into the outer reaches of Mugaari Space, sometimes going further to connect with worlds controlled by two other relatively close alien civilizations, the Lutrillians and Nothoiin. These natives had engaged in sporadic trade with the Republic for centuries, but reaching their respective homeworlds of Lutrillia and Nothoiin required lengthy and slow detours around the sprawling Twin Nebulae gas clouds, and the Mugaari demanded a large share of the profits.
After a swift and one-sided war, the Republic emerged victorious over the Mugaari. The Republic then forcibly annexed the eleven worlds of Mugaari Space as Republic cartographers formed the expansive new Javin sector within the Outer Rim Territories. Despite the efforts of numerous hyperspace explorers, a more direct route to Lutrillia and Nothoiin would remain undiscovered for many years.
The Republic's takeover of regional power in the former territories of Mugaari Space facilitated the establishment of numerous newly settled worlds along the Corellian Trade Spine, including Mexeluine, Gerrenthum, Indellian, Bendeluum, Ione, Darlyn Boda, Orn Kios, and Isde Nada. Ships scouting from Gerrenthum, under the direction of entrepreneur Ecclessis Figg, eventually succeeded in charting new star lanes directly through the Twin Nebulae, connecting the Trade Spine to Lutrillia and Nothoiin. Figg's remarkable achievement transformed the collective region into a major economic center.
Following their species' defeat by the Republic, the majority of Mugaari abandoned the planet Javin, which had been the most populous Mugaari world after Mugaar itself. The Mugaari held resentment towards Humans, viewing them as invaders and occupiers, and they despised the Lutrillians and Nothoiin for their collaboration.
The Galactic Republic–Mugaari war was first detailed in "Galactic Gazetteer: Hoth and the Greater Javin," a 2004 online supplement for the Star Wars Roleplaying Game by Wizards of the Coast.