Naga Sadow, also known as Darth Naga Sadow was an ancient Dark Lord of the Sith preceeding Darth Marka Ragnos during the Great Hyperspace War of 5,000 BBY. He killed his master, Simus and then launched the Great Hyperspace War against the Republic and the Jedi, but failed to conquer them and his Sith Empire was destroyed. So Naga killed his arch rival, Ludo Kressh and fled into exile on Yavin IV and built up his own Sith Temples there with his Massassi followers.
After centuries of attempts to rebuild, a fallen Jedi named Freedon Nadd came to the Sith Temples and was trained as a Sith by Lord Sadow. After completing his training, Nadd then killed Sadow and took on the title of Dark Lord. Sadow's burial chamber was then built by his followers deep in his Sith Temples.