7861933
Tulak Hord, enough said.

Naga Sadow imho.

7861934
Personally, I agree, and honestly, Ajunta Pall would be at the bottom of the list because he redeemed himself with the help of Revan, even though that subject differs from playthrough to playthrough since there's a light side, dark side, and neutral option for Revan's interactions with him

Naga Sadow. He remained a threat far longer than most.

I'm torn between Tulak Hord and Marka Ragnos.