The Praetor Mark II-class battlecruiser, alternatively known as the Praetor II-class Star Battlecruiser, constituted a warship type that saw action within the ranks of the Imperial Navy. This class belonged to the Star Destroyer design lineage, recognized by its distinctive wedge-shaped structure.
The Praetor Mark II, considered the largest battlecruiser configuration on record, exhibited a dagger-like form, akin to other prominent warships serving the Imperial Navy, and was a member of the KDY Star Destroyer design family. Similar to the Bellator-class dreadnought and the Assertor-class Star Dreadnought, the Praetor Mark II-class battlecruiser incorporated a central "ridge" structure that ran from the ship's rear to the midpoint of its front. This ridge on the Praetor Mark II also extended beyond the main thrusters, behind the stern. The Praetor Mark II varied in size from 4,800 meters to about 8,000 meters, the latter equaling five Imperial II-class Star Destroyers. This greater length technically qualified it as a Star Dreadnought based on the Anaxes War College System, despite its lighter armament compared to typical Star Dreadnoughts, leading to its designation as a Battlecruiser.
The Praetor Mark II was equipped with three primary engines along with four secondary engines. Two of the secondary engines were positioned on the outer sides of the ventral section, and the remaining two were located directly behind the ridge extension on the stern. Much like the Executor-class Star Dreadnought, the Praetor Mark II concealed its reactor equipment behind substantial armor, lacking a visible ventral reactor bulb.
The Praetor Mark II battlecruiser was armed with a minimum of 90 weapon emplacements, featuring diverse spherical turrets situated on the dorsal, ventral, and trench areas. Furthermore, its hull armor and deflector shields were sufficiently robust to withstand standard blaster fire.
At its front, the Praetor Mark II featured a docking bay area shaped like a triangle, which appeared only marginally larger than the main docking bay found on an Imperial-class Star Destroyer. Furthermore, this class of vessel included rings situated near the ship's rearmost section, behind the bridge. This transport ring was capable of holding supplies, equipment, and even living specimens, such as the Teezl creature. It was operated by a crew of 109,000 individuals, encompassing both officers and enlisted personnel. In addition, the Praetor Mark II could accommodate 120 starfighters alongside various shuttles, barges, and walkers.
In contrast to the later Vengeance-class dreadnought, the Praetor Mark II did not utilize a T-shaped KDY-style bridge tower. Instead, the command bridge was situated at the front of the ship's elevated ridge. Showing similarities to the bridge tower of the Venator-class Star Destroyer and Acclamator-class assault ship from the Clone Wars era, as well as the later Secutor-class Star Destroyer, the bridge was positioned closer to the surrounding superstructure, presenting a smaller target compared to those designs. The internal bridge section possessed a notably larger volume than a typical Star Destroyer bridge, accommodating numerous fleet officers for meetings within the space.
Crew quarters were situated within the dorsal ridge, while the remaining areas of the ship were dedicated to machinery, control systems, and engineering spaces.
The Praetor Mark II was conceived and manufactured early during the Galactic Empire's rule, acting as a successor to the smaller Praetor-class Star Battlecruiser from the Republic era. The number of ships from this class that were commissioned was limited, as Imperial tactical doctrines favored more massive dreadnaughts over battlecruiser designs for their terror-inducing effect. Coupled with a higher cost than individual Star Destroyers and reduced versatility, production of the Praetor Mark II was halted.
Owing to the Empire's strategic priorities, the _Mark II_s, along with other battlecruiser designs, were mainly deployed to safeguard critical locations within the Core region. Select battlecruisers were also assigned to especially hazardous missions at the fringes of Imperial territory, though they seldom ventured from their berths except for significant engagements.
A prominent instance of the latter involved the Helmsman, commanded by Admiral Mils Giel. The Helmsman was tasked with leading a secret armada to transport a Teezl from the Valtha Divide to Coruscant. This Teezl, a living hyperspace communications device, was intended to enhance Navy communications, facilitating improved coordination against Rebel forces. The Helmsman housed the creature within its transportation ring.
The secret armada came under attack en route, resulting in the death of the Teezl by Rebel forces. The formidable armor and shields of the Praetor Mark II necessitated modifications to the stolen TIE fighters utilized by the Rebel Flying Bantha Squadron, enabling them to breach the Helmsman's defenses and target the transportation cage. Although damaged, the vessel survived the assault, with its gun batteries immediately attempting to retaliate, but the assailant TIE fighter escaped.
A Praetor Mark II participated in a fleet exercise alongside several other Super Star Destroyers sometime after the Arms Race campaign. During this exercise, an Assertor-class dreadnought and an Allegiance-class battlecruiser were simultaneously refueled by a large replenishment ship.
The Thalassa represented a Praetor Mark II under the command of Admiral Sander Delvardus. Delvardus headed the Eriadu Authority, which seceded from the main Galactic Empire following the Battle of Endor.
During the New Republic's offensive against the Imperial warlords, a task force consisting of EF76 Nebulon-B escort frigates and BTL Y-wing starfighters fought the Thalassa in 4 ABY. It was engaged and destroyed by the task force within the Moorja system.
The design of the Praetor Mark II-class battlecruiser was derived from concept art created by Ralph McQuarrie during the pre-production phase of Star Wars: Episode V The Empire Strikes Back. This concept was one of several considered for the Super Star Destroyer Executor. This artwork was subsequently repurposed to depict Admiral Giel's flagship within the secret armada featured in the Marvel Star Wars comics.
Neither the ship class nor Giel's flagship received a specific name within the comic itself, and were sometimes referred to as Super Star Destroyers by fans due to their wedge-shaped design and overall larger size than a Star Destroyer.
It was not until the publication of The Essential Guide to Warfare in 2012 that the ship class, along with Giel's flagship, were officially named. Ansel Hsiao, a 3D fan artist, also produced artwork of the ship specifically for the book.