Sith Lord: A Sith who has mastered the Force, not just the Dark Side of the Force. Second only to the Dark Lord, they train as many apprentices as they want to.
Sith Master: A Sith who has mastered the Dark Side of the Force, but not the Light Side. A Sith is awarded this rank when they successfully train an apprentice to the status of Sith Marauder. Sith Masters are limited to training three apprentices at a time. This rank is the Sith equivalent of the Jedi Master.
Sith Marauder: This is the most common Sith rank. A Sith is given the title «Darth» upon reaching the rank of Sith Marauder. Sith Marauders are limited to training one apprentice at a time. This rank is the Sith equivalent of the Jedi Knight.
Sith: A Sith in training. The rank of Sith often coincides with the successful construction of a lightsaber. This rank is the Sith equivalent of the Padawan.
Sith Apprentice: The lowest Sith training rank. An apprentice is usually less powerful and less experienced than a Sith. This rank is the Sith equivalent of the Jedi Initiate.