One of the five pillars of The Sith Council, chiefly for Religion/Cultist types.
Led by Reyven Samoth.
The cultist Sith preaches the religion of the Dark Side, guiding the followers of the Order to maintain them on a path that will lead to Sith dominance. They are often collectors of those who have yet to find their way to the Dark Side and are used to convert fallen Jedi. They speak before every big gathering to remind the brethren what it means to be a Sith. (Perhaps the cultist Paladins could be used to "recruit and gather" new potential Sith. These might be the guys that take the Jedi POWs for torture or whatever.)