The Interdictor-class Star Destroyer is a capital ship available to the Imperial Remnant throughout the game. It carries an armament of four Turbolasers (firing eight pulses each), a Dual Heavy Turbolaser (five pulses), and two Ion Cannons (14 pulses), as well as four fighter and bomber squadrons and a gravity well generator, which prevents opponents from retreating until the hardpoint is destroyed or the ability deactivated.
Sienar Fleet Systems had already designed an interdictor, the Immobilizer 418 Cruiser, built off the hull of the 600-meter-long Vindicator-class Heavy Cruiser. Although relatively well armed for its size, the Immobilizer was a high priority target and could not hold its own in direct combat. Kuat Drive Yards, in an attempt to rectify this and supplant SFS as the supplier of interdictors, built its new Interdictor Star Destroyer on the significantly larger hull of an Imperial I-class Star Destroyer. In order to house the gravity well projectors, half of the weaponry had to be removed and the hanger size was reduced, decreasing the fighter compliment to 4 squadrons. Being more heavily armored and armed, the Interdictor Star Destroyer did not require additional support in performing patrol and customs duties. However, like the Immobilizer, the gravity wells remained a large drain on the ships main reactor, making it unfit for direct combat duties.
Ever since its conception, the Interdictor-class was an significant addition to the Imperial fleet. As it required less support, it was often used against pirate insurrections and isolated pockets of rebellion. They were also used during raids and invasions to prevent enemy escape.
After the Battle of Endor, the Interdictor-class remained in Imperial service. It was used extensively during Grand Admiral Thrawn's campaign against the New Republic. Thrawn ingeniously used them on occasion to pull his own fleet out of hyperspace, making the jump much more efficient, allowing the incoming vessels to scramble into a situation with unprecedented precision.
The Interdictor-class Star Destroyer is the third of four capital ships available to the Imperial Remnant (and the third used throughout the game). Unlike the other ships (ISD I and II, Tector), the Interdictor is a support capital ship and is not meant for direct combat. It is designed to prevent enemy ships from escaping from hyperspace with its gravity well generators. However, unlike the fragile Immobilizer, which has to be placed out of combat in order for it to survive, the Interdictor can be placed in direct combat situations without fear of its shields being overwhelmed.
Its primary weaknesses are its lack of weapons for a ship of its size, the reduced fighter compliment, and the fact that it must remain stationary when the gravity wells are being projected. Large groups of fighters and bombers are deadly to them, as are more than one ship targeting it at once (it doesn't carry the armament needed to destroy them quickly). Nonetheless, the Interdictor remains at least a competent frontline combat vessel, unlike the Immobilizer, which will crumble if confronted with serious opposition.