The only other "Sith" lurking at this time that aren't Bane's sith are the Lost Tribe of the Sith. But they are stuck on a god forsaken planet, where no other civilization knows there location, and are basically just twiddling there thumbs until they are found in "Fate of the Jedi". That's why i said there should only be 2 sith AFFECTING THE GALAXY. Because i know there are actually more sith in the GFFA then just Bane's Sith. However the only sith that are really affecting the galaxy in negative ways (trying to cause havoc, destroy the republic/jedi, etc) are the "Order of the Sith Lords". This is there moment to shine. Yes more Sith groups then just the Lost Tribe would exist. But Lumiya's sith and the One Sith havn't been created yet, they are only created after RoTJ.