The Imperial Commando Special Unit represented an elite special forces division within the Galactic Empire. Initially created from the Republic Grand Army's Special Operations Brigade during the Clone Wars, approximately one thousand commandos remained at the war's conclusion. These surviving squads were restructured into a special division inside the 501st Legion, which was the personal stormtrooper unit directly answering to the Sith Lord Darth Vader.
In the early period of the New Order, Imperial commandos frequently received missions centered on hunting down and assassinating adversaries of the Galactic Empire, encompassing Jedi fugitives, clone renegades, and deserters. Initially, the unit was under the command of Sa Cuis, an Emperor's Hand, but following his demise, Commander Roly Melusar took over. The original Imperial commandos included three members of Delta Squad: Boss (IC-1138), Fixer (IC-1140), and Scorch (IC-1262); Sev had gone missing during a mission. Commandos who survived from Omega Squad and Galaar Squad were consolidated into Squad 40.
The first Imperial commandos under the New Order were former Republic commandos from the Grand Army's Special Operations Brigade. As the Clone Wars ended and the Galactic Empire rose in 19 BBY, the remaining commandos were reassigned to the 501st Legion, an elite stormtrooper unit led by the Sith Lord Darth Vader. This new organization, known as the Imperial Commando Special Unit, continued to be made up of genetically-identical soldiers originating from the same clone line that produced the Republic clone troopers. However, nearly everything else about the commandos, including their armor, designations, and even their squads, was modified to align with the Empire's Imperialization policies.
The Imperial commando numbers did not match the original strength of the Special Operations Brigade at the start of the Clone Wars. Besides confirmed desertions, the three years of civil war resulted in significant casualties, leaving the Empire with approximately one thousand clone commandos. To supplement the millions of new clone soldiers within the Stormtrooper Corps, Arkanian Microtechnologies produced Spaarti-engineered clones to bolster the commando ranks. The original commandos, bred using Kaminoan techniques, were secretly resentful of the introduction of clones from the Arkanian Centax-2 batch, viewing them as inferior troopers with inadequate training. While former Republic commandos formed the majority of the Imperial Commando Special Unit, some Alpha-class ARC troopers were also recruited into the 501st to train new generations of the Empire's elite shock troopers.
Following Emperor Palpatine's ascension to absolute power, the commandos exchanged their Katarn-class armor for new armor, lacking unit markings and personal customizations, reflecting the New Order's emphasis on uniformity and obedience. Squads that had sustained losses were either reinforced with new members or merged with other squads. Sev, the missing member of Delta Squad, was replaced; the remaining members of Galaar Squad and Omega Squad were combined to create Squad 40. However, their identification numbers, aside from the IC prefix, remained unchanged. In addition to keeping their designations, the commandos were initially allowed to retain the DC-17 rifle, primarily because it was their familiar weapon.
While Darth Vader held overall command, Imperial commando operations were more closely supervised by a subordinate of the Dark Lord of the Sith. Their initial commander was Sa Cuis, a Dark Jedi and Force-sensitive assassin known as an Emperor's Hand. After Cuis's death, an Imperial officer named Roly Melusar assumed leadership of the Imperial commandos.