Well, perhaps this is one prominent group that no one knows about. If Kreia's words are meant to be taken literally, they are running an entire empire in secret.
But I agree with what adamqd is saying: this group of Sith should not have some sort of vendetta against the Jedi or the Republic. If my theory stated about is correct, then such a vendetta would not be logical as these Sith departed from Ziost to build their empire before the Republic and Jedi Order even existed.
Perhaps their qualm is actually with the other Sith? Now that would be interesting. If they see the other Sith (i.e the Dark Jedi Sith) as somehow a continuation of the weaklings they abandoned on Ziost, believing them to be unworthy of being Sith; and they view the current Sith as somehow connected to or a continuation of those "weaklings" back on Ziost who now dare to attempt galactic domination and act as if they know everything there is to know about the dark side of the Force; perhaps these "true Sith" believe that these heretics need to be destroyed. And perhaps Revan saw the coming clash between these two Sith groups as a major threat to the Republic sitting in the middle, which was why he went to eliminate the threat before it had a chance to strike.
Originally Posted by a silly noob
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