Well, he said greatest, not most powerful.
From a certain point of view, Xendor could be the greatest; his actions led to everything that came later that had to do with the Dark Side.
Desann and Jerec were decently powerful. Numerous Emperor's Hands were powerful.
You would just have to take your pick.
Originally posted by Ianus
I got a better question...Who cares?
lol, i don't..
just asked to ask.
You still didn't tell me how you pronounce your name correctly. Remember I ask in the other post? Just wanna know.
And I would say Dooku before he became Sith, right after being Qui-Gons Master and he dropped out of the order. Which was probably during and probably well before the events of Ep. 1.