The clash known as the Battle of Mon Calamari represented a significant battle, pitting the forces of Darth Krayt's Galactic Empire against the surviving elements of the Galactic Alliance Remnant. This conflict unfolded during the broader Second Imperial Civil War in the year 137 ABY.
The planet Mon Calamari held a longstanding allegiance to the Galactic Federation of Free Alliances, following in the footsteps of the New Republic and the earlier Rebel Alliance. In the seven years following the Alliance's defeat in the Sith–Imperial War, the Mon Calamari people consistently supplied crucial resources such as spare parts, bacta, and fresh recruits to the Galactic Alliance Remnant, all under the leadership of Admiral Gar Stazi.
Even though the Quarren held governance over the world and the Imperial presence was established, certain influential Mon Calamari and Quarren individuals recognized the imperative to bolster the struggling Galactic Alliance remnant. Gial Gahan, a former member of the Alliance Triumvirate, played a key role in devising a scheme to seize the new Advanced Star Destroyer named Imperious, which was nearing completion within the Imperial-controlled Mon Calamari Orbital Shipyards. By strategically sabotaging the computer networks governing the Shipyards' automated defenses, Gahan created an opening for the Alliance fleet to enter the system and capture the advanced Star Destroyer. However, Stazi, cautious of a potential Imperial deception, deployed only a single Alliance task force, personally leading the operation.

Unbeknownst to Gahan, the former Triumvir, Imperial Admiral Dru Valan had orchestrated a carefully laid trap intended for Stazi's forces. Despite his suspicions, Stazi still moved forward with the attempt to commandeer the Imperious.
Valan's forces, having strategically positioned stormtroopers aboard the newly constructed Star Destroyer, launched an ambush against the Alliance commando units as they infiltrated the vessel. As Admiral Stazi's forces, spearheaded by the Indomitable, entered the system, Valan's Outer Rim Third Fleet materialized at Calamari, effectively trapping Stazi between his own fleet and the planet's formidable defense systems. Valan communicated with Stazi, demanding his surrender under threat of annihilation. Stazi, echoing his decision from Caamas, firmly refused to yield. However, Valan was unaware that Stazi had anticipated his trap and had prepared a counter-strategy of his own.

Stazi issued the order for his fleet to unleash a barrage of fire upon Valan's forces. The sudden and intense assault from the Alliance fleet caught the Imperials off guard, resulting in notable damage to the Relentless. Valan responded by commanding a return volley, supplemented by fire from the shipyards' automated weapon emplacements. However, the automated defenses, having been reprogrammed by Monia Gahan, turned their fire against the Imperial fleet. The combined firepower of the Alliance fleet and the shipyard's defenses inflicted considerable damage on the vessels of the Outer Rim Third Fleet. Despite ordering the immediate shutdown of the shipyard's defenses, Valan remained confident, believing that Stazi was cornered.
Simultaneously, the stormtroopers that had ostensibly retaken control of the Imperious were, in reality, Alliance operatives under the command of Hondo Karr. They successfully hijacked the Advanced Star Destroyer and piloted it to a secure Alliance base.
Valan dismissed the loss of the Imperious as a minor setback, asserting that the Empire could easily reclaim it at a later time. He then directed his forces to focus on destroying the Indomitable, identifying Stazi as the linchpin of the entire Alliance rebellion. While the remainder of the Alliance fleet executed an evacuation from the system, Stazi deliberately positioned his vessel to absorb the brunt of the Imperial fire, while Alliance CF9 Crossfire starfighters engaged the Imperial Predator-class fighters.
Once the safety of the remaining fleet was assured, Stazi commanded the evacuation of all personnel from the Indomitable with the exception of himself, intending to ram the vessel into the shipyards to deny their use to the Empire. However, Rogue Leader Jhoram Bey incapacitated Stazi and evacuated him against his will. Subsequently, Captain Yorub assumed command of the Indomitable and, despite a desperate barrage of fire from Valan's fleet, successfully rammed the ship into the shipyards, resulting in the destruction of one-third of the facility and damage to an additional quarter.

The engagement concluded as a resounding triumph for the Alliance. They had not only managed to escape with minimal losses and inflict damage on the Empire's shipbuilding infrastructure, but they had also acquired a vessel capable of outmatching the Empire's most advanced warships.
In the aftermath of the battle, the Alliance task force convened at their designated rendezvous point to evaluate the outcome of the engagement. Stazi promoted Jhoram Bey to the position of Captain Yorub's second in command. He also informed Jhoram of the necessity to prepare the fleet for future operations, anticipating that the Sith would seek retribution for the theft of the Imperious.
Meanwhile, aboard the Relentless, a dismayed Admiral Valan delegated the responsibility of composing a report to Darth Azard, the Sith Lord overseeing the Third Fleet, through his aide, Captain Hoge, granting him complete discretion over the report's contents. Having once again failed to defeat Stazi, he retreated to his private quarters, contemplating ending his own life.
Darth Krayt, already enraged by Cade Skywalker's escape from his grasp, journeyed to Dac accompanied by a contingent of Sith Lords to unleash his fury upon the Mon Calamari, exterminating ten percent of their population and consigning the remainder to forced labor camps as punishment for their support of Gar Stazi. The first victims of this purge were the members of the Mon Calamari Council.
Unbeknownst to both the Alliance and the Sith Empire, operatives of Fel's Empire had sabotaged the Imperious. Three explosive devices (one intentionally poorly concealed, the others more carefully hidden) had been rigged to destroy the ship as soon as its weapons systems were activated, with the intention of ensuring the explosion occurred far enough from the shipyards to prevent blame from falling on the Mon Calamari. As the Alliance was still viewed as a potential ally by Emperor Fel, Imperial Knights Treis Sinde and Sigel Dare rescued Monia Gahan and, at Gahan's urging, numerous other stranded Alliance personnel, enabling them to reach the Alliance fleet and warn Stazi. Master Sinde remained behind to engage in combat with Darth Azard, allowing the others to escape. After successfully evading Azard, Sinde established contact with a Mon Calamari resistance cell to continue the struggle against the Sith Empire.
The Battle of Mon Calamari appears to draw inspiration from the St Nazaire Raid of 1942 during World War II. In that raid, British forces successfully destroyed the dry docks at the German-occupied French port of St Nazaire, preventing Nazi Germany from utilizing the docks for extended naval operations in the Atlantic campaign. Similarly, the Sith's campaign of genocide against the Mon Calamari seems to be based on Adolf Hitler's Commando Order, which mandated the summary execution of captured Allied commandos.