Grand Marshal Crisis

The Grand Marshal Crisis was a three-year period in which an insidious figure called the Grand Marshal emerged, attacked and destroyed key New Republic bases, gaining a stranglehold on the Outer Rim, while also carving a path to the Deep Core by conquering several worlds in the Inner Rim and Expansion Region, reaching the Core Worlds before disintegrating when the Marshal and his Sith patron, the Dark Lady Moha, were decisively defeated on Had Abaddon.

The Marshal's aims were multifarious and were primarily a reaction against Daala's concentration of Imperial power into her hands and the subsequent formation of the Imperial Remnant. The Marshal gathered the bulk of his forces from the fragments he had been able to command following the disastrous defeat of the Dark Empire on Byss, and had further absorbed the Restored Empire's forces after its collapse by invoking the authority of none less that Grand Moff Wilhuff Tarkin, thought dead after the Battle of Yavin.

In truth, the so-called "Tarkin" which was presented to the remaining Imperial factions was nothing more than an advanced artificial intelligence not unlike the Second Imperium scam, with the sum total of the Grand Moff's ideology and speech patterns programmed into it, with the ability to make new stratagems and even give commands; a Clawdite named Mec Lifton was employed for occasions when personal contact was required. The ruse was abandoned following the failed destruction of the Jedi Praxeum and the Great Temple on Yavin 4, apparently to avenge the Imperial defeat there thirteen years ago.

Following the emergence of the Grand Marshal Faction, its focus shifted to the restoration of the Sith Empire as the Marshal came increasingly under the sway of Moha, self-proclaimed Dark Lady of the Sith at the end of the New Sith Wars, whose Force ghost was encased in the Sith holocron which had given him his power in the first place. To this end, a number of diversionary sieges were conducted in the Outer Rim whilst the Marshal's fleet rapidly engaged and neutralised New Republic bases in a path directed at Had Abaddon, an ancient Sith planet in which Moha's carbonite-embedded body, along with those of her Lost Legion, had been hidden since the end of the New Sith Wars.

However, the situation was complicated by the Marshal's unleashing of the greatest failure of the Order of the Silver Jedi against the New Jedi Order: The so-called Run'chakaar (lit. "Soul Thief"), a failed experiment by the Order to create the perfect Force Being, which instead mutated into a creature which could only live by subsisting on the Living Force of other beings, killing them in the process. Luke Skywalker and Harlan Ysanna came under attack by the Run'chakaar as it hunted down the New Jedi Order's students due to their Force-sensitivity, and without their help the New Republic failed to prevent the Marshal's forces from punching a path directly to Had Abaddon. However, these aims were never to be realised as Luke Skywalker and his student Harlan Ysanna were able to intercept the Marshal and Moha before they could resurrect the Sith Master.

With the final destruction of Moha and her Sith army, and the defeat of the Marshal, his forces proved to be unable to sustain their grip on the conquered worlds, and the entire movement disintegrated within the year; those troops which did not surrender to the New Republic either joined the Imperial Remnant or scattered into various disunited cells and gangs.

Origins
The Grand Marshal also had a personal cause for starting the crisis: Even though he had these motivations, he had no opportunity - until it was dropped into his lap, four years later.

Then a Commodore, he was making a report in the Imperial Palace when Palaptine's death had sparked off riots in the city. In the confusion, he broke into Palaptine's office, and found two important objects: one of Palpatine's holdout lightsabers and a Sith Holocron, made by Darth Vectivus, detailing the location of the Dark Side Pyramids. He went there and gained much power. With this power, he swayed several governers and commanders into giving him their planets, building up his strength and his military might. It is estimated he had more than two thousand ships under his command at the peak of his power.