The Dreadnaught cruiser was a type of warship used by the Sith fleet of the Brotherhood of Darkness toward the end of the New Sith Wars. In 1001 BBY, three Dreadnaught cruisers formed a part of a Sith fleet that attacked a Galactic Republic naval force in orbit around the planet Ruusan. During the surprise attack, the Dreadnaughts targeted with their laser cannons two of the Republic's Hammerhead-class cruisers, whose shielding had been compromised, although the Sith craft were forced to abandon their advance when their quarry deployed starfighter squadrons against them. Approximately a year later, the Sith used Dreadnaught cruisers to blockade Ruusan so as to prevent a Jedi fleet from landing reinforcements to aid an ongoing ground campaign on the planet, and eventually the Dreadnaughts went on to engage the Jedi capital ships in combat.
The Dreadnaught cruiser, which shared its name with the type of capital ship known as the dreadnaught, was a type of warship equipped with hyperdrive engines and armed with several forward-mounted laser cannons.
Despite having less firepower, Dreadnaught cruisers could still pose a threat to the Galactic Republic's 315-meters–long Hammerhead-class cruisers once the latter's primary deflector shields had been disabled. In turn, a sufficient number of Republic starfighters could deter an advance by Dreadnaught cruisers. After using the Dreadnaughts in a surprise attack on a Republic fleet, the Brotherhood of Darkness also utilized the vessels to enforce a planetary blockade in order to prevent a Jedi fleet from landing reinforcements.
In 1001 BBY, as part of the New Sith Wars, the Sith navy of the Brotherhood of Darkness launched an attack on a Galactic Republic fleet stationed in orbit around the Mid Rim planet Ruusan. The Sith force included the Brotherhood's flagship, the Sith Destroyer Nightfall; three Dreadnaught cruisers; two corsair battleships; and multiple interceptor and Buzzard starfighters. The Republic fleet, consisting of four Hammerhead-class cruisers and three battleships, had more starships with greater firepower, but Dark Lord of the Sith Skere Kaan both used the element of surprise to the advantage of the Sith and coordinated the attacking force via the use of the battle meditation Force technique.
During the First Battle of Ruusan, Dreadnaught cruisers attacked Galactic Republic Hammerhead-class cruisers (a vessel of the latter class pictured).
The large Sith fleet—carrying out a dangerous maneuver for a force of such size—emerged from hyperspace en masse, beginning to bombard the Republic vessels before they could even sound an alarm. When two of the Hammerhead cruisers lost their primary shields after suffering a strafing run by the Sith Buzzards, the Dreadnaught cruisers moved in to attack with devastating efficiency the suddenly-vulnerable capital ships.
However, one of the Republic fleet's cruisers was carrying aboard a Jedi Master who was also proficient in the use of battle meditation. After the Jedi began applying the technique to the Republic's benefit, the Hammerhead cruisers being targeted by the Dreadnaughts rapidly—and unexpectedly so to Kaan—deployed four full squadrons of Aurek-class tactical strikefighters, which forced the Sith vessels to break off their attack run since they were coming under an assault by the Republic fighters. Ultimately, however, the Sith prevailed in the battle, in which the Republic fleet was completely destroyed.
Dreadnaught cruisers were used by the Sith to blockade the planet Ruusan.
Later, the Sith forces became involved in a protracted ground campaign on Ruusan against the Jedi Army of Light led by Lord Hoth. Subsequently, the Brotherhood of Darkness's navy established a planetary blockade in order to prevent a Jedi fleet mustered by Lord Valenthyne Farfalla from landing reinforcements to aid Hoth's efforts. The Sith fleet, which was commanded by Admiral Adrianna Nyras and was nearly double the size of the newly arrived Jedi naval force, included Dreadnaught cruisers and other vessels.
Since the Jedi fleet lacked the starfighters necessary to break the troop transports through the blockade, and since the relations between Hoth and Farfalla had become strained, the force did not engage the Sith fleet and simply waited outside the latter's targeting range. Around one year after the First Battle of Ruusan, however, Dark Lord of the Sith Darth Bane ordered the Brotherhood's fleet to engage the assembled Jedi force. The Jedi capital ships were targeted by the Dreadnaught cruisers, and several Jedi gunships used the opportunity provided by the Sith fleet breaking formation to finally land on Ruusan. Soon thereafter, the ensuing final battle on Ruusan saw the Jedi and the Republic emerge victorious in the overall war.
An excerpt from a Wookieepedia article on the Dreadnaught cruiser (bottom columns; in Aurebesh, transliteration available here) was presented as in-universe text on a data screen in the Star Wars: The Clone Wars episode "Cat and Mouse."
The Dreadnaught cruiser was introduced in the 2006 novel Darth Bane: Path of Destruction, authored by Drew Karpyshyn as the first entry in the Star Wars: Darth Bane Trilogy.
In "Cat and Mouse," the March 26, 2010 sixteenth episode of the Star Wars: The Clone Wars television series' second season, a data screen aboard the Galactic Republic Star Destroyer Resolute displayed tactical information on the Separatist dreadnaught Invincible. The data on the screen also included, transliterated in the Aurebesh script, an excerpt from an article on the Dreadnaught cruiser from the free-to-edit, unofficial online Star Wars encyclopedia known as Wookieepedia. When asked about the canonicity of the said excerpt and the information contained therein, Lucasfilm Story Group member Matt Martin stated that he considered it an Easter egg, therefore implying that it was not canonical with respect to either the current Star Wars canon or the franchise's Star Wars Legends continuity.