Freedon Nadd - Sith Lord or Dark Jedi?
"Other fallen Jedi, not content to serve their comrades, struck out on their own, spreading the darkness. One such was Freedon Nadd. Nadd roamed the uncharted systems until he found a world he could dominate through the dark side. The planet was called…Onderon."
―From the holocron of Vodo-Siosk Baas
"Freedon Nadd was a Dark Jedi. The stories say he was far worse than Revan and Malak ever were."
―Xarga
Now, I know there are 'sources' that state he is a Sith Lord. But it is more likely due to the fact that he was apprenticed to Naga Sadow and the Sith-ic bond he had with Lord Sadow. But then again, maybe I am wrong: and it is a retcon?