The Acolyte episode 6 reveals that Qimir was once a Jedi, leading to a theory about how the Sith stayed hidden for so long. The Sith may have hidden among the Jedi Order's ranks, practicing the ...

The Sith, which is a religious dark side order, have existed in the shadows for thousands of years thanks to the Rule of Two. There can only ever be two Sith Lords at once a Master and an Apprentice.