The MC75 Star Cruiser, alternatively known as the MC75 modified star cruiser, represented a class of Star Cruiser actively deployed by the Alliance Fleet. A notable vessel of this type, the Profundity, functioned as the flagship for Admiral Raddus during the critical engagement known as the Battle of Scarif. Additional examples included the vessels Aspiration, Accordance, Silver Coronet, and Temperance.
The MC75 Star Cruiser, also known as the MC75 modified Star Cruiser, started as a Mon Calamari city-ship that was transformed into a war cruiser by the Alliance to Restore the Republic. This substantial craft had a length of 1,204.44 meters and drew power from a dozen Kuat Drive Yards Gemon-15 sublight ion drives. These drives were adapted to grant the large vessel a cruising velocity comparable to starfighter escorts. These sublight drives were positioned beneath the engineering plane of the heat-dissipating engineering structure.
The transformation process involved extensive modifications at deep-space facilities, which included reinforcing the original city-ship's hull and adding heavy armor. This provided protection comparable to battleship hulls, along with a weapon collar modification to support primary weapons and shield generators. Superior shielding was installed on the front and rear of the superstructure. The armored forward hull made the ship's hidden deflector shield generators unnecessary, although a deflector shield emitter array was added to the rear. The MC75 was armed with twenty point-defense laser cannons, a dozen broadside turbolasers, four heavy ion cannons, twelve proton torpedo launchers, and six tractor beam projectors. These were concealed within a port forward of the weapon collar, enabling it to engage larger warships of the Imperial Navy.
An armored outrigger fin on the ventral hull housed the command bridge pod and receiver array, positioned opposite a dorsal communications transmission mast and sensor cluster. These blade-like fins, along with the vessel's tapered shape, were designed to evoke primal fears of predatory fish in the aquatic Mon Calamari. An ordnance pod was located next to the rear of the ventral outrigger fin. The city-ship's former civic atrium was emptied and repurposed as a docking bay and starship service area, managed by a hangar traffic control suite with overlapping shields and magnetic containment fields to maintain oxygen and pressure. The docking bay and service area could accommodate ships up to corvette size.
During the Imperial Era, the ship class had at least two variations, namely the MC75 Armored Cruiser and the MC75 Ordnance Cruiser, which shared a similar appearance.
MC75 Star Cruisers were used as passenger liners and transports for civilian purposes. They served as the initial true command ships for the Alliance Fleet, and because only a limited number were in service at any given time during the war, they were often commanded by Alliance admirals. These cruisers were rarely deployed independently, typically operating with a dozen or more supporting vessels.
Typical tactics for an MC75 involved maintaining a long-range position from enemy warships, engaging them with turbolaser fire in small groups of two or three. When necessary, MC75 cruisers could maneuver between ships to unleash broadsides against enemy targets. In situations requiring increased firepower, MC75 cruisers would usually move to medium range to deploy their ion cannons. MC75 Star Cruiser crews were tasked with adjusting the ship's shields to protect the side facing the most intense fire. When confronting smaller warships or starfighters, MC75 Star Cruisers typically fired their laser cannons and torpedoes in groups of two or three.
In 18 BBY, the Galactic Empire occupied the ocean planet of Mon Cala. This event prompted the indigenous Mon Calamari to initiate a mass departure from their homeworld, taking many of their large city-ships with them. The MC75 Star Cruiser was the first of these city-ships to be converted from civilian to military applications. Originally, MC75 Star Cruisers were utilized as passenger liners, civilian transports, and civic governance centers. The MC75 Star Cruiser Profundity, which functioned as a transport and passenger liner, originally served as the civic governance tower in Nystullum. It was among the first vessels converted into warships by the rebellion at deep-space facilities. The MC75 Star Cruisers represented the initial wave of ships to escape Mon Cala, with subsequent waves following later. As the Mon Calamari left their world, they committed their cruisers to the Alliance war effort.
By 2 BBY, after Phoenix Cell acquired a Quasar Fire-class cruiser-carrier in the Ryloth system, the Telaris rebel stardocks had been converted into war production facilities. These facilities began refitting the MC75 Star Cruiser Profundity alongside the MC80A Home One Type Heavy Star Cruisers Home One and Nautilian. Colonel Anj Zavor's report to Commander-in-Chief Mon Mothma regarding operations in the shipyards within the Telaris cometary cloud was included in The Rebel Files. By 1 BBY, the Profundity was among the first battle-ready capital ships and became the flagship of Admiral Raddus, the former mayor of Nystullum, and the Alliance Fleet.
After Rogue One disobeyed orders from Alliance High Command and infiltrated Scarif to steal the Death Star plans, the Rebel Alliance decided to deploy its forces to assist, leading to the Battle of Scarif, a crucial battle in the Galactic Civil War. Admiral Raddus commanded Alliance forces from the bridge of the Profundity and eventually received a rebel transmission containing the plans from Scarif's surface. Before the Profundity and the remaining Alliance ships could escape, the Death Star and the Imperial flagship Devastator arrived. This resulted in the destruction of several Alliance ships, and the Profundity sustained damage, preventing its escape and leading to a boarding action led by Darth Vader. Following the Imperial boarding, Raddus was killed and rebel troops were massacred. However, the Death Star plans were successfully transferred to the Tantive IV, which was docked in the hangar and managed to escape.
With the loss of Admiral Raddus and the Profundity, Admiral Gial Ackbar assumed command of the remaining Alliance Fleet elements not deployed to Scarif. Before the Battle of Yavin, Admiral Ackbar submitted a report to Commander-in-Chief Mon Mothma, detailing the defense of Yavin 4 and the potential threats posed by Imperial actions. In this report, Admiral Ackbar emphasized that despite the loss of the Profundity, the fight continued with the Home One serving as the new Alliance flagship. Ackbar's report was also included in The Rebel Files. By this time, several other MC75 Star Cruisers had completed their refits and were assigned to Alliance operational areas.
Following the mutiny of the Mon Cala Mercantile Fleet, at least five MC75 Star Cruisers were present at the Mako-Ta Space Docks. During the Galactic Civil War, at least one Rebel Alliance MC75 star cruiser participated in a battle above Cianap against Imperial forces led by Darth Vader. On one occasion, an MC75 Star Cruiser was damaged in an engagement and sought refuge from Imperial reinforcements within a protostar's cloud. The ship's navicomputer was damaged, necessitating a new navigational database to initiate a lightspeed jump before the cloud's radiation compromised the entire ship.
Also during the Galactic Civil War, an MC75 Star Cruiser with red livery engaged an Interdictor-class heavy cruiser and other Imperial forces. The MC75 Star Cruiser was supported by at least two EF76 Nebulon-B escort frigates and starfighters. The MC75 Aspiration participated in a battle and inflicted damage on an Imperial Victory-class Star Destroyer.
On the same day as the Battle of Endor, the MC75 Star Cruisers Temperance and Accordance participated in a battle in the Hosnian system against an Imperial armada that attempted to attack the Core Worlds. The battle concluded with an Alliance victory, although the Accordance was destroyed, and its survivors were rescued by the Temperance.
Following the Battle of Endor, the Alliance transitioned into the New Republic, and the New Republic Defense Fleet continued to use MC75 Star Cruisers. The Temperance was placed under the command of New Republic General Hera Syndulla after her flagship, the Acclamator-class assault ship Lodestar, was destroyed during a campaign in the Cerberon system. The Temperance was deployed during the Troithe operation, where it bombarded the Scar of Troithe. Around this time, the Temperance served as the headquarters of Vanguard Squadron, which were deployed around the Bormea sector to defend the New Republic's Project Starhawk, its shipbuilding project to construct Starhawk-class battleships.
In 34 ABY, after The Rebel Files were recovered by the Resistance, Ackbar and Ushos O. Statura added annotations to Zavor's report to Mothma about the Telaris rebel stardocks and the status of the Profundity.
In 35 ABY, Imperial Galactic Emperor and Dark Lord of the Sith Darth Sidious had returned and threatened the galaxy with the destruction of every major world who resisted him. In response, Lando Calrissian and the Resistance led a massive fleet, which included dozens of MC75 Star Cruisers and subvariants in the climactic Battle of Exegol over the Sith world of Exegol. When the Resistance returned to Ajan Kloss to celebrate their victory, at least one MC75 was present on the planet.
The MC75 Star Cruiser made its initial appearance in the live-action film Rogue One: A Star Wars Story in 2016. The ships reappeared in the 2019 movie Star Wars: Episode IX The Rise of Skywalker, with several variants, including versions lacking towers or featuring additional engines. This was because during the creation of the Galaxy Fleet, the designers encountered difficulties in designing 16,000 ships before the film's premiere. Consequently, they reused the model, and computer programs began to mix and match component parts for certain ships to enhance their uniqueness.