Autumn of the Republic
Three hundred years ago, after the final defeat of the Sith, the Republic began an expansive piece of legislation called the Ruusan Reformation, which put the Jedi Order under the oversight of the Supreme Chancellor and Senate (as well as enacting many other structural changes), and disbanded the Republic military, relying on the Jedi and planetary militaries for protection.
The Duros, who have long excelled as pilots and adventurers, saw this as a remarkable opportunity to expand their reach and protect the Republic they loved. They began building a great fleet of quick, maneuverable fighters and organized starfighter corps for loan to worlds that lacked a military to defend themselves. Looking to expand their services further, the Duros also began training a military force of guerillas and engineers to serve as ground security, favoring speed and efficiency over brute force.
The Duros fleet is made up of a few larger capital ships, which usually function as command ships, led by an admiral. Under his or her command are various commanders, captains, and pilots, flying starfighters of different roles (interceptors, bombers, defense fighters, etc.) for whatever need they are called to fill. Their ground forces tend to also fall under the control of this admiral, but they also defer to ground sergeants and majors.
The Duros, seeking lucrative defense contracts, have come into conflict with the more aggressive Trandoshan military, who tend to pursue aggressive ground combat strategies. The two have developed something of a professional rivalry, and a Duros pilot and Trandoshan soldier may come to blows if left together too long—or they may bond over kill counts and tours of duty.