The Interdictor-class was a model of Star Destroyer derived from the Imperial-class Star Destroyer that was active during the Imperial Era. The Galactic Empire utilized the Interdictor-class and the other models of the Imperial-class to inspect vessels along their patrol routes. An Interdictor vessel, it had four gravity well projectors and was 1,600 meters in length. Admiral Gable Karius, commander of the Imperial garrison stationed at Fortress Vader on Mustafar, utilized one such Interdictor to capture a smuggler, their First Mate ZO-E3, and their starship, the Windfall. During Crimson Dawn's war against the Sith, the Imperial Navy deployed an Interdictor-class to end Lady Qi'ra's Crimson reign, but Crimson Dawn's flagship Vermillion directly crashed into the Interdictor, destroying both ships.
The Interdictor-class was a class of 1,600-meter-long Star Destroyer and Interdictor vessel, derived from the Imperial-class Star Destroyer. As such, it was dagger-shaped with a raised command structure atop of which the conning tower sat. Distinct from the other Imperial-class vessels, however, was a separation on the command levels, with a large substructure between the hull and where the bridge was situated. Two deflector shield generator domes were positioned atop its command structure at the port and starboard sides, with a communications tower between them. The hull was gray in color.
The Interdictor-class was equipped with turbolasers which were to the aft of the four—two starboard and two port—spheroidal gravity well projectors. The gravity well projectors were powerful enough to create an artificial gravity well called an interdiction field. This field could be used to prevent ships from jumping into hyperspace, as well as taking ships out of it. The starship had a small ventral hangar bay placed forward of a larger ventral hangar and a ventral solar ionization reactor between its projectors. The Interdictor-class was further equipped with three Destroyer-I ion engines and four Gemon-4 ion engines for emergency use. The interior of the Interdictor-class consisted of hallways and compartments, which included walls lined with controls and at least one viewscreen that could be used to communicate with other starships.
At times, Interdictor-class starships were deployed with other Imperial-class Star Destroyers of the Galactic Empire to pull vessels from hyperspace at key locations along their patrol route and board them for inspection.
The Imperial Navy fielded a number of Interdictors during the Empire's reign. One such Interdictor was under the command of Admiral Gable Karius, commander of the garrison stationed in Fortress Vader, on the volcanic planet Mustafar in 1 BBY. During the vessel's time there, it captured the smuggling starship Windfall, pulling it out of hyperspace and placing it above Mustafar. ZO-E3, First Mate of the Windfall, was confused about how they could have been caught in hyperspace and placed in the Atravis sector of the Outer Rim Territories.
Following an encounter with TIE fighters, and once the Interdictor-class came in view of the Windfalls cockpit, ZO-E3 stated that the Star Destroyer was unlike any she had previously witnessed. ZO-E3 and her captain, a Force-sensitive smuggler, were soon contacted by Admiral Karius, who communicated via a two-way viewscreen from the Interdictor. Subsequently announcing himself, the admiral ordered the Windfall to cede control of their ship to the Star Destroyer. After initial backlash, the crew conceded and allowed the Empire to take control and move the vessel from Mustafar's orbit to the hangar of Fortress Vader on the surface while under a TIE escort.
By 0 ABY, a particular model of Interdictor cruiser, the Immobilizer 418 cruiser, was no longer manufactured by the Empire due to its vulnerabilities. The Empire favored placing the gravity well projectors on Star Destroyers instead, as they were more difficult to eliminate. The Empire also canceled production of the Interdictor-class heavy cruisers, as they ultimately proved an easy target for rebels; their gravity well projectors were placed inside standard Star Destroyers instead. Rebel Alliance lieutenant and Jedi Luke Skywalker recounted the Immobilizer 418 cruiser's halted manufacturing and the implementation of the projectors on Star Destroyers after he and his ship, the Desert Jewel, were pulled out of hyperspace by an Immobilizer in the Daalang system and fought against Imperial forces.
Following the commencement of the Crimson Dawn syndicate's secret war against the Sith, which began between 3 ABY and 4 ABY, the Empire hunted down Crimson Dawn's forces throughout the galaxy. Eventually, the Imperial Navy discovered Crimson Dawn's flagship, the Vermillion, on the surface of a terrestrial astronomical object.
The Imperial fleet forces were led by an admiral and consisted of an Interdictor-class and an Imperial-class Star Destroyer. From the Imperial-class, the admiral ordered the Interdictor's crew to activate their gravity well projectors to prevent Crimson Dawn forces from escaping. A battle ensued when the Vermillion attacked the Interdictor-class and surrounding TIE line craft, flying directly towards the Interdictor. Unable to stop its momentum, the Vermillion crashed into the Interdictor-class, destroying both ships in a large explosion. With the Vermillion destroyed, Emperor Palpatine believed that Crimson Dawn leader Lady Qi'ra had perished. Unbeknownst to him, Qi'ra was actually transmitting from the starship Siroto and escaped the Empire's capture. After the battle, the Interdictor-class's wreckage appeared on a screen in the Siroto.
The Interdictor-class was first mentioned, albeit indirectly, in the current Star Wars canon in Heir to the Jedi, a novel authored by Kevin Hearne and published on March 3, 2015. The starship was subsequently identified in the twentieth issue of the Star Wars: Build the Millennium Falcon magazine by De Agostini, released around May 20, 2015.
The Interdictor-class made its visual debut simultaneously on September 26, 2018 in a news segment on the YouTube-based web series The Star Wars Show and in a promotional image in a news article on StarWars.com, both announcing the virtual-reality video game Vader Immortal: A Star Wars VR Series – Episode I as the first episode of Vader Immortal: A Star Wars VR Series produced by ILMxLAB. The game was released in 2019, marking the ship's first appearance. The Interdictor-class was simply referred to as a Star Destroyer in the script for Vader Immortal, according to a Twitter post by Lucasfilm Story Group executive Pablo Hidalgo.
In the Star Wars Legends continuity, the Interdictor-class Star Destroyer first appeared in the fifth issue of the Star Wars: X-Wing Rogue Squadron comic book series, which was published by Dark Horse Comics on February 13, 1996. The issue was authored by Darko Macan and Michael A. Stackpole, with illustrations provided by Edvin Biuković. The vessel subsequently received its name in the twenty-first issue of the magazine The Official Star Wars Fact File, which was published in 2002.