"Vader's set up a special assassination unit of former Republic commandos and ARCs within the Five-oh-first solely to hunt Jedi, deserters and sympathizers."
"Your former special forces comrades are adept at causing death and chaos. So you are the ones best placed to locate and neutralize them. I expect no quarter given to them. They were your brothers once, but they are now traitors, an insult to all of you and your sacrifices. You are now the Imperial Commando Special Unit. Do not disappoint me."
The Imperial commando ranks did not reflect the full strength that the former Special Operations Brigade started with at the beginning of the Clone Wars. In addition to several confirmed deserters, attrition due to three years of civil war inflicted heavy casualties on them, leaving the Empire to inherit roughly a thousand clone commandos by the end of the conflict.[1] In addition to the millions of new clone soldiers that swelled the ranks of the Stormtrooper Corps,[2]Arkanian Microtechnologies produced Spaarti-engineered clones for the purpose of replenishing the commando ranks.[1] The original commandos that were bred via Kaminoan techniques[2] were secretly agitated by the introduction of clones from the Arkanian batch of Centax-2,[1] whom they regarded as subpar troopers with inferior training.[2] Though the former Republic commandos composed the vast majority of the Imperial Commando Special Unit, a number of Alpha-class ARC troopers were also recruited into the 501st ranks to train new generations of the Empire's elite shock troopers.[1]
In the days that followed EmperorPalpatine's rise to absolute power, the commandos replaced their old Katarn-class armor for a new suit of armor,[2] devoid of unit markings and personal customizations[1] in accordance with the New Order's emphasis on uniformity and obedience.[5] Squads that had suffered one or more losses were either given new replacements or combined with other squads. The former Delta Squad's RC-1207 was replaced by a new commando; the remaining members of Galaar Squad and Omega Squad were amalgamated to form Squad 40. However, their identification numbers, apart from the IC prefix, remained the same. In addition to retaining the same designations, the commandos were permitted to keep the DC-17 rifle for a time, mostly because it was the primary weapon that they were accustomed with.[1]