D-Squad was a squad within the military forces of the Galactic Republic during the Clone Wars conflict. This unit was composed of four astromech droids: R2-D2, QT-KT, U9-C4, and M5-BZ, along with one DUM-series pit droid known as WAC-47. The command of D-Squad was given to Colonel Meebur Gascon. Some years afterward, during the Galactic Civil War, R2-D2 reformed the squad, adding new members to oppose the Scourge, a dangerous droid entity.
D-Squad was a droid team of the Galactic Republic assembled for a mission: to steal an encryption module from a Separatist Providence-class Dreadnought. Though they succeeded, D-Squad's shuttle (their) crashed on the planet of Abafar. While stuck on the desert world, the droids encountered an amnesiac clone commando known as CC-5576-39, or "Gregor." With the clone's assistance, Gascon and the squad were able to leave Abafar.
After their escape from Abafar, D-Squad came across the Renown, a lone Venator-class Star Destroyer, above the planet. At first, Gascon thought the Galactic Republic had come to rescue them. However, upon reaching the Star Destroyer's bridge, they found that Separatist forces had taken control of the ship. After evading the battle droids, D-Squad discovered a detonator and that the cruiser's docking bays were full of rhydonium, a highly explosive substance.
D-Squad later encountered a small group of Republic droids, including servant droid BNI-393, who explained that the Separatists had seized the starship and intended to destroy the space station Valor, the location of the Republic strategy conference.
Eventually, a buzz droids discovered D-Squad's location. BZ decided to open the airlock to force the buzz droids into hyperspace as they closed in. While the other droids magnetized themselves to the metallic surface, BZ failed to do so in time and was pulled out of the Star Destroyer along with the buzz droids. After this loss, Gascon gave a short speech to commemorate BZ's sacrifice.
When the cruiser exited hyperspace above Carida, where Valor and more than a dozen other Star Destroyers were in orbit, D-Squad managed to evacuate while R2 detonated the explosives early, preventing the Separatists from destroying the space station. D-Squad initially believed R2 was lost, but General Anakin Skywalker dispatched several salvage teams to find and rebuild R2. After the incident, D-Squad and Colonel Gascon were reassigned to the same platoon.
Between 3 ABY and 4 ABY, during the Galactic Civil War, R2-D2 reformed the team to fight the Scourge, which had started corrupting droids across the galaxy. Bounty hunters 4-LOM and IG-88, along with assassin droids BT-1 and 0-0-0, joined the new team. QT-KT later rejoined R2-D2 and became a member of the squad as they journeyed to Jabba's Palace on Tatooine. Joined by warrior-priest droid Ajax Sigma, D-Squad attacked the Scourge's headquarters, the converted Star Destroyer Scourge 01, where Sigma destroyed the Scourge's main body, ending its threat and freeing all those it had corrupted from its control. Sigma invited the members of D-Squad to join his Second Revelation church, but they refused. 0-0-0 further cautioned him against becoming a threat that would require D-Squad to reform and fight him.