The Imperial-class Star Destroyer (ISD) known generally as the Imperial Star Destroyer or as an Impstar, was a product line of massive dagger-shaped capital ships of the Imperial Navy of the Galactic Empire and later the naval branch of the First Order. It consisted of three variants, the Imperial I-class, the Imperial II-class, and the Interdictor-class.
The Imperial–Star Destroyer replaced the smaller Venator-class used by the Galactic Republic during the Clone Wars and was generally the Galactic Empire‘s star cruiser of choice.
At the height of its power, the Empire operated over 25,000 Star Destroyers. The distinctive profile of the Imperial-class instilled fear into the soldiers of rebellious factions, and the name of a Star Destroyer could be preceded by the ship prefix ISD (standing for Imperial Star Destroyer). In a report to an admiral, Senior Commander Alecia Beck referred to the ISD Vehement.
Roughly thirty years after the Battle of Endor, the new Resurgent-class Star Destroyers were constructed to replace the aging Imperial-class by the Empire’s successor state, the First Order, and would borrow design philosophies from the highly respected and coveted ship.