The Battle of Mon Calamari was a major battle between Darth Krayt's Galactic Empire and the Galactic Alliance Remnant, which took place during the Second Imperial Civil War in 137 ABY.
The world of Mon Calamari was a longtime supporter of the Galactic Federation of Free Alliances, as well as the New Republic and Rebel Alliance that preceded it. In the seven years following the defeat of the Alliance in the Sith–Imperial War, native Mon Calamari provided spare parts, bacta, and recruits to the Galactic Alliance Remnant, under Admiral Gar Stazi.
Despite the fact that the Quarren were now in control of the planet and the world was under Imperial occupation, several key Mon Calamari and Quarren saw that more was needed to aid the struggling remnant forces of the Galactic Alliance. Gial Gahan, a former member of the Alliance Triumvirate, helped hatch a plan to capture the new Advanced Star Destroyer Imperious, which was undergoing the final stages of construction in the Imperial-controlled Mon Calamari Orbital Shipyards. By sabotaging the computer systems that controlled the Shipyards automated defense systems, Gahan allowed the Alliance fleet an opportunity to jump into the system and seize the new Star Destroyer. Stazi however, wary of an Imperial trap, sent only a single Alliance taskforce, with himself in command.
The Mon Calamari shipyard defenses open fire.
However, former Triumvir Gahan was unaware that Imperial Admiral Dru Valan had planned a trap for Stazi's forces. Although he already expected as much, Stazi still attempted to hijack the Imperious.
Stationing stormtroopers on the new Star Destroyer, Valan's forces ambushed Alliance commando units infiltrating the vessel. Once Admiral Stazi's forces jumped into the system led by the Indomitable, Valan's Outer Rim Third Fleet appeared at Calamari, trapping Stazi between his fleet and the planet's defense systems. Valan contacted Stazi and told him to surrender or die. Stazi, repeating his choice from Caamas, refused to surrender. But what Valan didn't know Stazi had been prepared for his trap all along and had set up one of his own.
One third of the Mon Calamari shipyards is destroyed.
Stazi ordered his fleet to open fire on Valan's fleet. The sudden barrage from the Alliance fleet took the Imperials by surprise, and was able to inflict some damage to the Relentless. Valan ordered a return fire and fire from the automated guns on the shipyards. But the automated guns fired on the Imperial fleet, having been hacked by Monia Gahan. The combined fire-power of the Alliance fleet and the shipyard's guns inflicted heavy damage on the ships of Outer Rim Third Fleet. Valan ordered the shipyard's defenses to be shut down, but was still confident because he had Stazi trapped.
Meanwhile, the stormtroopers that had re-seized the Imperious were actually Alliance troops under the command of Hondo Karr. They hijacked the Advanced Star Destroyer and got it to one of the Alliance bases.
Valan brushed off the theft of the Imperious, saying the Empire could easily recapture it later. Valan ordered his forces to destroy the Indomitable, saying Stazi was the key to the entire Alliance rebellion. While the rest of the Alliance fleet evacuated the system, Stazi had his ship take the Imperials' fire, while the Alliance's CF9 Crossfire starfighters fought the Imperial Predator-class fighters.
After the rest of the fleet was safe, Stazi ordered the entire crew of the Indomitable evacuated save himself, as he planned to ram the Indomitable into the shipyards so the Empire couldn't use them. However, Stazi was knocked out by Rogue Leader Jhoram Bey and evacuated. Instead, Captain Yorub took command of the Indomitable and, despite a desperate barrage of fire from Valan's fleet, rammed the ship into the shipyards, destroying a third of them and damaging a quarter.
The Imperious with the Galactic Alliance Remnant fleet.
The battle was a major victory for the Alliance. Not only had they escaped with minimal casualities and inflicted damage to the Empire's ship building capabilities, but they now possessed a ship that could out-gun the Empire's best ships.
Following the battle, the Alliance task force gathered at their designated rendezvous point where they assessed the results of of the battle. Stazi promoted Jhoram Bey to Captain Yorub's position as his second in command. He also told Jhoram that they needed to ready the fleet for further action, as the Sith would seek retribution for the theft of the Imperious.
Meanwhile, aboard the Relentless, a shocked Admiral Valan left the task of writing a report to Darth Azard, the Sith Lord overseeing the Third Fleet, to his aide, Captain Hoge telling him to report whatever he desired. Having failed to defeat Stazi once again, he retired to his quarters, contemplating suicide.
Darth Krayt, already furious that Cade Skywalker had escaped from his clutches, traveled to Dac with an entourage of Sith Lords to unleash his wrath upon the Mon Calamari, exterminating one-tenth of them and ordering the rest to be placed in work camps, for their assistance to Gar Stazi. The first to be executed were the members of the Mon Calamari Council.
Unbeknownst to both the Alliance and the Sith Empire, agents of Fel's Empire had sabotaged the Imperious. Three sets of explosives (one deliberately hidden poorly, the others more carefully concealed) had been rigged to destroyed the ship as soon as its weapons were brought online, which was expected to occur far enough from the shipyards that the Mon Calamari would not be blamed. As the Alliance was still considered a potential ally by Emperor Fel, Imperial Knights Treis Sinde and Sigel Dare rescued Monia Gahan and, at Gahan's insistence, numerous other downed Alliance personnel so that they could reach the Alliance fleet and warn Stazi. Master Sinde remained behind to fight off Darth Azard, allowing the rest to escape. After Sinde escaped from Azard, he made contact with a Mon Calamari resistance cell to continue the fight against the Sith Empire.
The Battle of Mon Calamari seems to be modelled after the St Nazaire Raid in 1942 during the Second World War . During the raid, British forces successfully destroyed the dry docks at the German-occupied French port of St Nazaire; denying Nazi Germany's usage of the docks for prolonged naval operations in the Atlantic campaign. Likewise, the Sith's genocidal campaign against the Mon Calamari seems to be based on Adolf Hitler's Commando Order which called for the summary executions of captured Allied commandos.