An Imperial trooper is actually a sleeper agent in disguise
A Sleeper Agent, alternatively referred to as a sleeper operative, represented a specific kind of spy whose operations involved prolonged periods of deep cover to accomplish a designated goal. These agents could be sentient organic being or droid. Some missions demanded that an agent remain undercover for durations spanning from months to even years. This necessitated exceptional commitment, along with the capability to convincingly deceive those in proximity and uphold a fabricated identity through a network of falsehoods. Typically, Sleeper Agents held ordinary positions that were unrelated to their actual mission objectives or targets. Seldom did agents occupy roles within government or military organizations, given the heightened levels of scrutiny and thorough background investigations associated with such positions. It's worth noting that certain Sleeper Agents functioned without conscious awareness of their true missions or actions, owing to methods such as brainwashing or reprogramming.
In the early stages of the Rebel Alliance's formation, Sabine Wren strategically infiltrated the Skystrike Academy under the guise of a pilot trainee. Her actual purpose centered around extracting Wedge Antilles, Derek Klivian, and Rake Gahree, all of whom expressed a desire to defect and join the Rebellion.
The C1-series astromech droid known as "Chopper" was briefly, and against his will, transformed into a sleeper agent working for the Galactic Empire. This was done by the crew of an Imperial IGV-55 surveillance vessel under the orders of Controller LT-319.
Through the implementation of Project Hidden Eye, the Imperial Security Bureau aimed to engineer sleeper operatives by utilizing cybernetics.
During the Galactic Civil War, the newly emerged criminal organization Crimson Dawn strategically placed sleeper agents within various factions throughout the galaxy, encompassing entities such as the Alliance to Restore the Republic, Galactic Empire, Tagge Corporation, Sixth Kin, and Black Sun.