Clone trooper film series and in the "Star Wars" expanded universe media, a number of specialized trooper units are seen, including elite special forces units such as the 'Advanced Reconnaissance Commandos' (ARC troopers), and Null ARCs, who usually work alone. All clone commandos and ARCs were trained by Mandalorian mercenaries; the elite Clone Troopers are known as Shadow Troopers. The style and color of a clone troopers armor often varies depending on their rank, specialization, unit, or environment, for example, the clone troopers on Kashyyyk wear camouflage green scout-style armour whereas the 501st legion wears standard white armor with blue accents. Another
Star Wars: Dark Forces a weakness in and subsequently destroy the Death Star. One year later, the Alliance hires Katarn again, this time to investigate an assault on one of their bases by a new type of Imperial soldier. His investigation reveals the Imperial Dark Trooper project, led by General [[List of Star Wars characters#M|[[Rom Mohc]] ([[Jack Angel]]). His mission to stop the project takes him to the sewers of [[Anoat|Anoat City]], where he captures [[Moff Rebus]], an Imperial weapons specialist who developed the Dark Trooper weapon. Rebus' interrogation leads Katarn to a weapons research facility in the mountains of Fest and the Gromas