Sources close to We Got This Covered (yeah I know) have told us that the show will revolve around Bautista’s character being the last Sith survivor after the climactic Jedi-Sith Wars (which took place roughly a millennium before the Skywalker saga). Though Darth Bane hasn’t been mentioned on the big screen, he’s a familiar presence to anyone who’s dipped their toe into the Star Wars novels, TV shows, comics and video games.
But while he might never have appeared in the movies, audiences will be familiar with his Sith philosophies. His analysis of why they were defeated by the Jedi was that they spent too much time squabbling amongst themselves for power, weakening themselves rather than presenting a united front. His reformed Sith featured the Rule of Two, which says that there can only be a master and apprentice Sith at any one time. The pair would operate in secrecy, with the apprentice killing the master when they became powerful enough, before taking an apprentice of his own.
Naturally, this proved fatal for him, as Darth Bane was murdered by his own student. But his plans eventually bore fruit in Revenge of the Sith, when Emperor Palpatine executed Order 66 and thus the long revenge of Bane was complete. For a couple of years, anyway.