Sith-Lords,
Black Lords and Sith Ladies, once called Jen'jidai (plural of Jen'ari), are the equivalent of the Jedi Masters in the Order of the Sith.
They are the most powerful Sith and lead the order. However, at different times this line was handled differently. Before 1003 VSY, the most powerful of the Sith led the order. His original title was Dark Lord of the Sith. The leader was later titled
Darth in front of his name to clarify his claim to this management position. The other Sith now all strove to amass more power than the leading lord in order to overthrow him. This ensured for a long time that the strongest of the Sith really led the order.
