Imperial Coalition
The Imperial Coalition was an alliance between the Ruling Circle and remaining fleet commanders in the days following the death of Grand Admiral Thrawn at the Battle of Bilbringi in 9 ABY. While the Coalition held the former capital of Coruscant in addition to vital Imperial worlds and star systems in the Deep Galactic Core as well as beyond Core Worlds, Imperial power remained dispersed. Thrawn's unfinished victory in his campaign fuelled conflict within the Empire, leading to the eruption of a full-scale Imperial Civil War within months that splintered Imperial forces until the return of Palpatine along with his Dark Empire in 10 ABY.
History
United for survival

Following the death of Grand Admiral Thrawn at the Battle of Bilbringi in 9 ABY, remaining fleet commanders joined the Ruling Circle to form the Imperial Coalition. The Ruling Circle was populated by the late Emperor Palpatine with his Dark Side Adepts, and was planned by Palpatine to eventually replace the system of Moffs and governors in the Galactic Empire to establish a dark side theocracy. Meanwhile, the fleet commanders held power over the remnants of the Imperial Military, wielding Star Destroyers and their accompaniments as forces of destruction.[1]
In addition to maintaining a hold over the Deep Galactic Core as well as many regions of high industry beyond the Core Worlds, the Coalition assaulted the New Republic after Thrawn's defeat at Bilbringi, recapturing vital planets and star systems in the Core. One such world was Coruscant,[1] captured in a battle led by General Alix Balan[2] in 10 ABY.[source?] However, the former galactic capital was not used as the prime base of operations.[1]
A fragile alliance

Nevertheless, Imperial Advisors such as Ars Dangor suggested that they convene in the old Senate building on Coruscant so that a new ruler be elected from amongst themselves, and that they establish themselves as the legislative body of the Empire there to oversee the newly-crowned ruler's decisions. Although Moffs and governors opposed and brought down the plan, the Commission for the Preservation of the New Order leadership was uneasy with what they saw as treasonous plotting in making decisions based on political convenience. Individual ministers, munitions tycoons, and functionaries immediately returned to their plotting, with the Inquisitorius doing likewise, exercising their power by staging show trials in their resentment of the Military's independence.[1]
The Military itself, both army and navy, gave themselves the power to appoint the new Emperor. The navy demanded the right to appoint a new Grand Admiral from their chain of command to resume the Thrawn campaign in addition, with the army wanting their say in the matter as well. The bureaucracy dismissed the military in response to the navy, claiming that Thrawn failed the Empire, and turned to regional militias and the CompForces instead.[1]
Shattered Empire
Violence ultimately erupted after months of political maneuvering within the Empire, as Thrawn's unfinished victory fuelled internal conflict to the extent of a full-scale Imperial Civil War. The Emperor's Ruling Circle came to blows against the military, instigating brutal fights of attrition involving a dozen loyalties where navy fought navy, orders of sieges and orbital bombardments were issued, terror troops destroyed planetary defense equipment, and anarchy reigned throughout cities. The presence of counter-insurgents and scavengers was rampant on the former Imperial capital.[1]
The war rendered Coruscant a disaster world, and though Palpatine returned with the Dark Empire in 10 ABY, the Emperor and his dark forces fell within a year, once again leaving Imperial forces to be consumed by greed. Despite this, New Republic planners had high hopes of remaking and rededicating Coruscant to the ideals of civilization as Imperials desperately clung onto what remained of their holdings.[1]