During the Imperial Era, the Interdictor-class Star Destroyer served as a type of Star Destroyer. It was a derivative of the Imperial-class Star Destroyer. To monitor vessels along their designated patrol routes, the Galactic Empire made use of the Interdictor-class, along with other Imperial-class models. This Interdictor ship stretched 1,600 meters and featured four gravity well projectors. Admiral Gable Karius, who commanded the Imperial garrison at Fortress Vader on Mustafar, employed one of these Interdictors to seize a smuggler, their First Mate ZO-E3, and their vessel, the Windfall. In Crimson Dawn's war against the Sith, the Imperial Navy sent an Interdictor-class ship to put an end to Lady Qi'ra's Crimson Dawn leadership. However, Crimson Dawn's flagship, the Vermillion, collided directly with the Interdictor, resulting in the destruction of both.
The Interdictor-class Star Destroyer was a Star Destroyer and Interdictor vessel that measured 1,600 meters in length and was a derivative of the Imperial-class Star Destroyer. As such, it possessed a dagger-like shape, with a raised command structure upon which the conning tower was located. In contrast to the other Imperial-class ships, there was a separation on the command levels, featuring a substantial substructure positioned between the hull and the location of the bridge. On the port and starboard sides of its command structure, two deflector shield generator domes were situated, with a communications tower positioned between them. The color of the hull was gray.
Located to the aft of the four spheroidal gravity well projectors (two on each side, port and starboard) were the turbolasers of the Interdictor-class. These gravity well projectors possessed sufficient power to generate an artificial gravity well, known as an interdiction field. This field had the capability to prevent ships from entering hyperspace and could also force ships out of it. The starship featured a small ventral hangar bay positioned forward of a larger ventral hangar and a ventral solar ionization reactor located between its projectors. Furthermore, the Interdictor-class was equipped with three Destroyer-I ion engines and four Gemon-4 ion engines for use in emergencies. The interior of the Interdictor-class consisted of corridors and compartments, including walls fitted with controls and at least one viewscreen that facilitated communication with other starships.
The Galactic Empire sometimes deployed Interdictor-class starships alongside other Imperial-class Star Destroyers to extract vessels from hyperspace at strategic points along their patrol routes and board them for inspection.
During the reign of the Empire, the Imperial Navy operated a number of Interdictors. One such Interdictor was under the command of Admiral Gable Karius, the commander of the garrison stationed at Fortress Vader on Mustafar, a volcanic planet in 1 BBY. During its service there, the vessel captured the smuggling ship Windfall, pulling it from hyperspace and positioning it above Mustafar. ZO-E3, the First Mate of the Windfall, expressed confusion about how they could have been intercepted in hyperspace and placed in the Atravis sector within the Outer Rim Territories.
Following an engagement with TIE fighters, and once the Interdictor-class became visible from the Windfall's cockpit, ZO-E3 remarked that the Star Destroyer was unlike any she had previously seen. Admiral Karius soon contacted ZO-E3 and her captain, a Force-sensitive smuggler, via a two-way viewscreen from the Interdictor. After identifying himself, the admiral instructed the Windfall to relinquish control of their ship to the Star Destroyer. Despite initial resistance, the crew complied and allowed the Empire to assume control, moving the vessel from Mustafar's orbit to the hangar of Fortress Vader on the surface under a TIE escort.
By 0 ABY, the Empire had ceased manufacturing a specific Interdictor cruiser model, the Immobilizer 418 cruiser, due to its vulnerabilities. The Empire favored installing gravity well projectors on Star Destroyers instead, as they presented a more challenging target. Production of the Interdictor-class heavy cruisers was also halted, as they proved to be an easy target for rebels. Instead, their gravity well projectors were integrated into standard Star Destroyers. Rebel Alliance lieutenant and Jedi Luke Skywalker recalled the cessation of Immobilizer 418 cruiser production and the incorporation of the projectors into Star Destroyers after an Immobilizer pulled him and his ship, the Desert Jewel, out of hyperspace in the Daalang system, leading to a fight against Imperial forces.
Following the start of the Crimson Dawn syndicate's covert war against the Sith, which took place between 3 ABY and 4 ABY, the Empire pursued Crimson Dawn's forces across the galaxy. Ultimately, the Imperial Navy located Crimson Dawn's flagship, the Vermillion, on the surface of a terrestrial astronomical object.
An admiral led the Imperial fleet forces, which consisted of an Interdictor-class and an Imperial-class Star Destroyer. From the Imperial-class, the admiral instructed the Interdictor's crew to activate their gravity well projectors to prevent Crimson Dawn forces from escaping. A battle broke out when the Vermillion attacked the Interdictor-class and the surrounding TIE line craft, heading directly for the Interdictor. Unable to halt its momentum, the Vermillion collided with the Interdictor-class, resulting in the destruction of both ships in a massive explosion. Emperor Palpatine believed that Crimson Dawn leader Lady Qi'ra had died with the destruction of the Vermillion. However, Qi'ra was transmitting from the starship Siroto and evaded capture by the Empire. After the battle, the wreckage of the Interdictor-class appeared on a screen in the Siroto.
The Interdictor-class Star Destroyer was first referenced, albeit indirectly, in current Star Wars canon within Heir to the Jedi, a novel penned by Kevin Hearne and released on March 3, 2015. The Star Wars: Build the Millennium Falcon magazine by De Agostini subsequently identified the starship in its twentieth issue, which was released around May 20, 2015.
The visual debut of the Interdictor-class occurred simultaneously on September 26, 2018, through a news segment on The Star Wars Show, a YouTube-based web series, and in a promotional image featured in a news article on StarWars.com. Both announcements concerned the virtual-reality video game Vader Immortal – Episode I, the first episode of Vader Immortal: A Star Wars VR Series produced by ILMxLAB. Released in 2019, the game marked the ship's initial appearance. According to a Twitter post by Lucasfilm Story Group executive Pablo Hidalgo, the Interdictor-class was simply referred to as a Star Destroyer in the script for Vader Immortal. The 2024 reference book, Star Wars Encyclopedia: The Comprehensive Guide to the Star Wars Galaxy, was the first source to formally identify the vessel as a "Interdictor-class Star Destroyer."
Within the Star Wars Legends continuity, the Interdictor-class Star Destroyer made its inaugural appearance in the fifth issue of the Star Wars: X-Wing Rogue Squadron comic book series, published by Dark Horse Comics on February 13, 1996. Darko Macan and Michael A. Stackpole authored the issue, with illustrations by Edvin Biuković. The vessel received its official name in the twenty-first issue of The Official Star Wars Fact File magazine, published in 2002.