As the Galactic Civil War came to a formal end, with the Imperial Remnant losing ground and ultimately signing the Pellaeon–Gavrisom Treaty with the New Republic in 19 ABY, many remaining Imperial warlords had turned to mass piracy. On the other hand, some Deep Core replacement warlords created the Second Imperium to continue the fight against the New Republic. but they were defeated by the New Republic and the New Jedi Order in 23 ABY.
In an effort to consolidate its power and enforce security, the New Republic tracked down and eliminated rogue Imperial warlords and pirates, focusing especially on their holdings in the Deep Core. These campaigns saw the initial trial of the Viscount-class Star Defender in 25 ABY, when the prototype Viscount engaged Imperial ships in combat. However, engagements were rare events.
On his side, Admiral Ackbar targeted remnants of the Second Imperium and liberated all remaining Imperium fortress worlds.
The outcome of these battles was the decimation of rogue Imperial forces and the end to organized Imperial piracy. Deployment of the Viscount during those skirmishes was considered as a huge waste of resources and the development of the Viscount-class program was soon stopped. The Viscount itself was later downgraded to ceremonial display. By the time of the Yuuzhan Vong War, the New Republic had finally cleared all the Imperial warlords out of the Deep Core. Admiral Ackbar would retire from service following the defeat of those last Imperial forces, in 25 ABY.
- Starships of the Galaxy, Saga Edition
- The Essential Guide to Warfare