"The Sith must be ruled by a single leader, the very embodiment of the strength and power of the dark side. If the leader grows weak another must rise to seize the mantle."
-Darth Revan's holocron

The title of Dark Lord of the Sith, or Jen'ari in the Sith language, originally referred to the ruler of the Sith Empire, and later was taken by the recognized leader of the Order of the Sith Lords. Before Kaan, there was only one Dark Lord of the Sith at a time, who was the head of the Order-in more recent periods, it was a title shared by multiple individuals simultaneously. The term referred to individuals of both sexes, though Lumiya claimed the title of Dark Lady of the Sith.

The title Dark Lord of the Sith is often thought to be synonymous with the title Darth. Contrary to this, however, is the fact that Sith apprentices have been known to carry the title as well. Two examples would be Darth Malak as Darth Revan's apprentice, and Darth Bandon as Malak's. Many Sith Lords have used the Darth title, but there is no evidence as to the synonymic relationship of these two appellations.

The title of Dark Lord was possibly comparable to that of a Jedi Grand Master.