Pre–Shadow Hand campaign

In 10 ABY, the forces of the Galactic Empire launched a multi-pronged campaign on the orders of the reborn Emperor Palpatine. The campaign, which soon dissolved into the Imperial Mutiny, was followed by Operation Shadow Hand.

Prelude
In the aftermath of the Battle of Endor, both the Galactic Empire and the Alliance to Restore the Republic thought Emperor Palpatine dead in the destruction of the Second Death Star. In fact, his spirit had survived and made its way to the Imperial redoubt of Byss in the Deep Core, where it spent a lengthy convalescence as it was reborn into a clone body. In the mean time, the New Republic advanced from Endor, slowly chipping away at a Galactic Empire that was torn by warlordism, until by 7 ABY it had captured Coruscant.

Prior to the Thrawn campaign of 9 ABY, Palpatine's clone slowly drew military forces into the Deep Core for a new offensive: Imperial Admiral Feyet Kiez abandoned Anaxes with the Star Dreadnought Whelm at Palpatine's orders, leaving even his second-in-command Osted Wermis none the wiser about his destination. The Imperial warlord-turned-pirate Inos Fonada disappeared down the Corellian Trade Spine with his fleet; the top designers of an Imperial research facility on Kelada vanished with all their weapons schematics; and after the seizure of Kuat, the entire senior Kuat Drive Yards design team fled into the Deep Core aboard the half-completed dreadnought Eclipse.

The New Republic mostly forgot about these reports during the near-disaster of Grand Admiral Thrawn's final campaign, and in its aftermath, reasserted its power with raids into the New Territories, conquering the Imperial Ruling Council's capital of Orinda and striking at the self-styled Prince-Admiral Delak Krennel's Ciutric Hegemony. Krennel was chosen due to his murder of Grand Vizier Sate Pestage several years earlier, and had continued to support his reign by bloody purges and repressing non-humans. The choice was seen as controversial by many, as Krennel had been relatively quiet since his rise to power and had not attempted to move outside the Hegemony. Aided by Ysanne Isard's clone, Krennel had helped this image by speaking out against superweapons, apologizing for the destruction of Alderaan, admitting the Empire had committed many wrong acts, and offering a refuge to Humans displaced by the New Republic's policies of reversing Imperial Human High Culture. As the policy continued, they were approached or had been approached by a number of refugee groups and other former Imperials, including Alderaanian refugees. They also had sent word to Gilad Pellaeon about bringing Thrawn's fleet into the Hegemony. However, the tide began to turn against them after the discovery of the plans for the Pulsar Station, a Death Star-like superweapon. In reality, the plans were false and had been planted by the real Ysanne Isard, who helped a New Republic force led by Rogue Squadron liberate the Hegemony and kill Krennel.

Meanwhile, Palpatine's agents made overtures to the Deep Core warlords, Blitzer Harrsk of Zero Command, Treuten Teradoc, and Sander Delvardus. The remnants of the Loyalist Imperial Ruling Council accepted the reborn Emperor as well, as did the otherwise-isolationist Pentastar Alignment led by Ardus Kaine. Most of the factions in Palpatine's alliance hated each other, but all feared both the Emperor's wrath and missing out on the cut of the spoils of a successful campaign.

Advance from the Deep Core
With Gial Ackbar and the New Republic Defense Fleet far out in the Outer Rim Territories pursuing warlords, the Core Worlds were left lightly defended, and Palpatine chose this moment to strike. Three enormous Imperial task forces advanced out of the Deep Core, anchored around four Executor-class dreadnoughts (including the missing Whelm), five Mandator III-class dreadnoughts, and three Vengeance-class dreadnoughts. The New Republic Navy, so long optimised for smaller cruiser and carrier-launched snubfighter action, proved to have no counter to the massive Star Dreadnoughts. The Deep Core fleets conquered Kaikielius and Alsakan. Meanwhile, High Admiral Treuten Teradoc struck Corellia.

The New Republic cobbled together a hasty defense at Metellos, but its fleets were caught completely out of position. Fleets sent from Imperial Space in the New Territories descended on the Core from the north while Sander Delvardus annihilated the fleet at Metellos. Meanwhile, the Ruling Council's forces advanced across the Borderland Regions, capturing Contruum and Columex.

The fall of Coruscant
Imperial fleets converged on Coruscant and initiated a savage bombardment of the planetary shields. With no hope of victory, Mon Mothma ordered an evacuation of the planet, carried out by Garm Bel Iblis. The New Republic resorted to guerilla fighting amid Galactic City, but ultimately lost the battle, and General Alix Balan led an Imperial triumph through the boulevards of Coruscant.

Aftermath
The New Republic's government regrouped on Da Soocha V in Hutt Space. They regarded the Empire's rapid new advance as unsustainable and awaited the opportunity to launch counterattacks. The newly-unified Empire, however, soon collapsed into a horrific six-way civil war between the Ruling Council, the Moffs, the Fleet commanders, the Inquisitorius, COMPNOR, and the Imperial Security Bureau that became known as the Imperial Mutiny. Coruscant was left a depopulated ruin. The cloned Emperor Palpatine did nothing to quell this fratricide, viewing it as "culling the weak", and instead used the opportunity to publicly reveal himself and deploy his World Devastator superweapons to Dac as part of Operation Shadow Hand.

The New Republic's poor performance against Imperial Star Dreadnoughts inspired the development of their own dreadnought analogues, the Mediator-class battle cruiser and the Viscount-class Star Defender as part of the New Class Modernization Program in the aftermath of Operation Shadow Hand.

Appearances

 * Dark Empire