Sith are mostly legend.  As are Jedi.  Knowledge of the Force in general is in decline, and especially in the outer reaches.<br/><br/>Just remember though, back 4k years ago, they were both a very real thing.  And to a certain degree they are, but it's like Ninja, everyone knows that they existed in some form, but their abilities and origins are getting very murky as more time goes by.  :-)