Darth Nihilus (II)

Ruber Sadow is a humanoid descendant of Naga Sadow, he turned to the dark side during the Great Galactic War in the Old Republic Era. After the war he took the remaing true Sith and once again fled into the unknown regions, only to return 10 years after the final death of Palpatine. He then "convinced" the Imperial Remnant to join him, and proclaimed himself the unchallenged "Dark Lord of the Sith".