4. Naga Sadow

Naga Sadow claimed the throne when Marka Ragnos died. A powerful Lord, and a highly skilled dark side magician, Naga Sadow was able to destroy stars with his Force abilities (and Sidious needed a Death Star to destroy planets).

He may have the loftiest ambitions of anyone on this list, because in addition to craving power, he felt that the Empire should rule the entire galaxy, with the Jedi and the Republic as new objects to be conquered rather than formidable enemies. But in addition to his expansionist ideas, he was the first Lord to actually acknowledge the Sith Empire’s issues and even attempt to fix them.

Like some of his list-mates, Naga Sadow’s greatest asset was his mind. He had no problem going toe-to-toe with his opponents, but he always knew his foes’ weaknesses prior to any encounter.

It would be interesting to see this character on the big screen, especially given how progressive his thinking is in comparison with the traditional power-hungry Siths we've seen so far.