The DT-series sentry droid, also referred to as the Imperial sentry droid, represented a droid line. These sentry droids were products of Baktoid Combat Automata, and the Galactic Empire employed them. These droids served in roles such as guards and combat training units. One particular training model found its post in Tipoca City on the extragalactic planet Kamino following the conclusion of the Clone Wars. Numerous droids were positioned on Imperial starships, including Class four container transports and Imperial Star Destroyers.
The DT-series sentry droid was a armed droid model used by both the Kaminoan government and the Galactic Empire; this wide use by the empire is why they were called "Imperial sentry droids." This droid was recognizable by its white-plating and wrist blasters on both of its arms. One DT-series variant was introduced in 19 BBY and was employed as training droids, though it could be fitted with live ammunition for lethal force. When not active, this variant was stored in lockers on racks. Another variant, featuring black and grey plating, existed by 9 BBY. It bore a strong similarity to the suits and droids manufactured under the dark trooper program. The DT unit D-L1T of this variant had white plating.
This sentry droid variant was based on old ST-series military strategic analysis and tactics droids and abandoned experimental droid designs. It was equipped with black plating and a built-in E-11 medium blaster rifle on either its right or left hand, depending on the specific unit. While it could still function as a training unit, these sentry droids were often used for guard duty. If one of these activated sentry droids was attacked during a deployment, the remaining deactivated droids would activate. They also had the ability to stun hostile targets. The droid was armored and could withstand multiple shots from small arms.
In 19 BBY, white-plated DT-series units were introduced as training droids by the Kaminoan government under Prime Minister Lama Su. In this capacity, many were stationed at the Tipoca City Training Facility on the extragalactic world of Kamino. Shortly after the end of the Clone Wars, Clone Force 99 faced a number of these sentry droids in a test of their effectiveness as the Galactic Empire began to build its military. On the orders of Admiral Wilhuff Tarkin, the droids used live ammunition against the clone commandos, surprising the squad. Nevertheless, they managed to defeat the training units. Impressed, Tarkin sent the commandos on a mission to Onderon, which ultimately changed his opinion of their usefulness, except for Crosshair.
Later, when Clone Force 99 returned to Kamino to rescue its sergeant, "Hunter," from Crosshair and his Elite Squad, the young clone Omega activated many of the sentry droids to save her squadmates from Crosshair's trap. This resulted in a large number of training units overwhelming the training facility where Crosshair held them captive. As Elite Squad Trooper ES-02 fled under fire from the training droids, Clone Force 99 joined forces with their lost brother to fight off the droids. Crosshair and his former squad managed to eliminate all the units Omega had activated before Admiral Rampart ordered the destruction of Tipoca City. Any surviving training droids were left to sink to the bottom of Kamino's seas after Rampart's bombardment destroyed the city.
By 9 BBY, Imperial sentry droids of the black and grey model were in service. In that year, they were part of the security detail for an Imperial Security Bureau (ISB) base in the Nova Garon system. Jedi Knight Cal Kestis invaded the base, using the power of the dark side of the Force to cause widespread destruction. Kestis, aided by his ally, the Nightsister Merrin, destroyed many sentry droids while retreating from the base and fighting a large group of them.
In 2 BBY, four Imperial sentry droids were stationed on an Imperial class four container transport trapped in the stormy atmosphere of Wynkahthu. When the Spectres and the pirates Hondo Ohnaka and Azmorigan boarded the ship, they accidentally reactivated one of the sentry droids. This droid knocked out Azmorigan and the rebel Garazeb Orrelios, throwing them into the ship's brig. Azmorigan later managed to shoot and destroy the droid. However, this activated the other sentry droids, who then attacked the rebels and pirates. The droids were destroyed when the container transport fell into a vortex.
Later, Grand Admiral Thrawn kept two sentry droids in his office aboard his flagship Chimaera for hand-to-hand combat practice. He used the override code "Rukh" to deactivate them when not in use. The "Fulcrum" operative Imperial Security Bureau Agent Kallus later reprogrammed these droids to attack Thrawn, creating a distraction for himself and his rebel comrades to escape.
Sith Lord Darth Vader used sentry droids as part of the security for his fortress on the volcanic planet Mustafar. When the Scourge, an artificial intelligence seeking to dominate the minds of organic and artificial beings, attacked Fortress Vader to control Vader, whom it saw as the key to controlling the power of the Force, some of the fortress's sentry droids were controlled by the Scourge to attack Vader. Although Vader was attacked while vulnerable, the Scourge's focus was divided due to a confrontation elsewhere, allowing Vader to recover and defeat the droids.
DT-series units were deployed on the planet Ryloth as part of the Imperial occupation effort. In this role, they worked alongside KX droids and organic personnel, such as stormtroopers, to maintain Imperial control despite the insurgency by the Free Ryloth Movement. The Scourge infected several DT and KX units on Ryloth while pursuing R2-D2, who was assembling a new D-Squad to defeat the Scourge once and for all.
Following the rise of the New Republic and the fall of the Empire in 5 ABY, Sentinel, a former stormtrooper who had abandoned the Imperial regime, became a Hunter in Hunters of the Outer Rim sporting matches. His on-stage persona was that of a loyalist stormtrooper who refused to accept defeat. Sentinel owned a suit of armor made from the remains of a DT-series droid, which he used in matches. The supposedly loyal Imperial once remarked that stormtroopers were superior to robots in every way, except that DT-series units were disposable while stormtroopers were not, even though the Imperial regime had treated stormtroopers as expendable.
The DT-series sentry droid first appeared in the Star Wars Rebels episode "The Wynkahthu Job." Its design was inspired by the Phase III dark troopers featured in the Star Wars Legends video game Star Wars: Dark Forces. Another version of the sentry droid, first revealed in the sizzle reel for Star Wars: The Bad Batch, appeared earlier in the Star Wars timeline in The Bad Batch episode "Aftermath." The official Databank on StarWars.com confirmed that this droid was the same type of sentry as those seen in Star Wars Rebels by using an image from The Bad Batch in the entry for the Rebels droids.