The qaz-class Star Destroyer represents a Star Destroyer type utilized by the Imperial Navy from the time the Galactic Empire was established. One notable vessel of this class was the Malevolence, a participant in the Galactic Civil War. Very soon after the Empire's formation, the destructive force generated by a test of an Imperial kyber-crystal-based weapon, which was connected to the development of the first Death Star, equaled the combined firepower of all weapon systems on a qaz-class Star Destroyer.
As a Star Destroyer model serving within the Imperial Navy, the qaz-class Star Destroyer was armed with numerous weapons emplacements.
From the start of the Galactic Empire in 19 BBY, the qaz-class Star Destroyer saw service. In 17 BBY, Project Celestial Power, an Imperial initiative, conducted a test firing of a kyber-crystal powered weapon. This weapon would eventually become the superlaser on the first Death Star battle station. Lieutenant Commander Orson Krennic ordered a Star Destroyer to fire two energy beams into the Hero Twins, a pair of black holes. Krennic then told Grand Vizier Mas Amedda that initial findings showed the weapon's energy release matched the total firepower of a qaz-class Star Destroyer. Amedda was pleased by this.
The qaz-class Star Destroyer known as the Malevolence entered service shortly after the Battle of Yavin during the Galactic Civil War. By this point, few qaz-class Star Destroyers remained operational, as the other ships had been retired. Around this time, Princess Leia Organa of the Rebel Alliance went on a mission to the planet Tibrin with Luke Skywalker. After Skywalker was captured and taken aboard the Imperial Star Destroyer Stormbringer, Organa infiltrated the ship to rescue him. To maintain her disguise, Organa claimed to have served on the Malevolence. However, stormtrooper TK-5648, who was checking incoming personnel, expressed surprise and wondered aloud what it was like to serve on a qaz-class ship.
The qaz-class Star Destroyer was initially referenced in Catalyst: A Rogue One Novel, a 2016 novel by James Luceno. In the audiobook, the name is pronounced "kazz." In the text, the designation is not capitalized or italicized, unlike other starship types such as the Imperial-class Star Destroyer.
Landry Q. Walker mentioned the qaz-class again in "The Trouble at Tibrin, Part II," a story featured in the fifth issue of the Star Wars Adventures comic series, released on December 27, 2017. The story's text is entirely in block capitals, so it provides no further information on the capitalization of "qaz," but it also left the term unitalicized.