In the New Sith Empire during the New Sith Wars, Sith Acolytes were dark side adepts considered sufficiently promising that they were viewed as candidates for elevation to the rank of Sith Lord. Assigned to the command of Sith Lords, Sith Acolytes were often charged with carrying out operations for their masters, and occasionally allowed subordinates of their own, such as non-Force-sensitives soldiers, assassins, or enforcers, or even less promising dark side adepts.
While trained in the dark side, often at the Empire's Sith academies, Acolytes lacked any of the protection given to Sith Lords. As such, they could be killed at will by their masters, or even other Sith. By contrast, killing a full Sith Lord without permission of that Lord's superiors merited a death sentence. As such, Acolytes competed for the favor of their masters, hoping to be referred to a Sith Overlord for elevation to lordship themselves. Elevation was often at the whim of superiors who might not wish to relinquish the power of life and death over their minions, and consequently some Acolytes were just as skillful and strong in the dark side as full Sith Lords.