The only surviving Sith Lord was Darth Bane (Mark Hamill), who witnessed all the destruction caused by the Jedi-Sith War and how his order was nearly wiped out. He developed a mortal grudge ...

The Dark Jedi then appropriated their name to become an organization ... became a Sith Lord, and returned centuries later as ...

When Palpatine gave in to the dark side and slaughtered his family, Damask helped cover up the crime, revealing himself as Darth Plagueis and recruiting Palpatine into the Order of the Sith Lords.