All the Sith Lords have died since their last stay on Roisan... all but one. The insidious "moral bombing" launched after the magnificent suicide of the Sith Lord Kaan destroyed all the Jedi Knights killed under the command of Lord Hoth. Everyone who was capable of using the Force on Ruasan was destroyed... all the warriors of both sides, light and dark. But other Knights remained The Jedi were outside the Republic, which meant that the Dark Brotherhood was now dead, with the exception of Darth Bane.