The Imperial Remnant
Following the destruction of the second Death Star and death of Emperor Palpatine...
the floundering Imperial Fleets fought a desperate, losing struggle to prevent the collapse of their authority. In short order, the Rebellion (renaming itself as the Republic) orchestrated a series of engagements that drove the Empire progressively farther into the Core.
When Coruscant fell, the Imperial High Command, lead by Supreme Commander Gallius Rax retreated to the fortress world of Prakith. Feigning weakness, Rax called upon Grand Moff Gaunt Sevrann to deliver a final blow to the nascent Republic via the Eclipse. This, due to events classified by the New Republic Military, never occurred. With Rax's death aboard his flagship the Ravager, Grand Admiral Sloane ordered the general retreat of Imperial forces, scattering the fleet to all corners of the Galaxy. Sloane herself disappeared along the Byss run, leaving a power vacuum that led to the dissolution of the Empire as a singular force.
Representatives of the Imperial government, captured on Prakith, would later offer their formal surrender to the New Republic. This would end the formal state of war and usher in the age of the Remnant warlords.
Criminals, Wastrels and Outcasts
The remnants left operating after the fall of the Empire are comprised of a loose coalition of Moffs, Rogue Admirals and other such iron-handed individuals. Existing only at the edges of the Republic's reach, these individual warlords rely on tenuous alliances with other such states to maintain their dominion over the few worlds they have claimed.
The largest of these states lay claim to one or two star systems, their military consisting of a few ill-maintained Star Destroyers and perhaps a legion of stormtroopers. The weakest of the warlords may possess only a single archaic corvette and a troop of former troopers. In aggregate, the remnant warlords remain a continuous threat to Republic reconstruction efforts. Yet, individually, each of these states would be easily crushed were they to awaken the ire of the galaxy's dominant power.
It is thus the policy of the New Republic to sew division and revolt within the ranks of these factions, rather than to contest them openly. The sudden reunification and reorganization of these disparate states under a single authority remains the foremost fear of New Republic Military strategists. With the disappearance of Grand Admiral Sloane and her contemporaries, however, it is widely accepted that no such individual or collection of individuals suited to the task currently survive.