*Using accolades/reasonable guesses/the limited feats we possess who would win a fight of the Sith spirits?
Marka Ragnos vs. JA Exar Kun vs. Freedon Nadd vs. Karness Muur vs. Ajunta Pall vs Naga Sadow
*Battle takes place in the temple of the Ancients
__________________ "Happiness is a lie. Life is horror. The light is always dying all across the universe. The last star will flicker out someday, when it does, all that remains is shadow. And I will be its king!"'-Amahl Farouk
Muur is my *favorite* sith spirt, but his disease power is pretty useless in a spirit fight.
Exar Kun's spirit was likely supercharged by all those lives used to make him a spirit, and he does have the best spirit feats, so yea, he probably does win.
__________________ "Vader's pulse and breathing were machine-regulated, so they could not quicken; but something in his chest became more electric around his meetings with the Emperor; he could not say how. A feeling of fullness, of power, of dark and demon mastery -- of secret lusts, unrestrained passion, wild submission -- all these things were in Vader's heart as he neared his Emperor. These things and more."
I put Pall and Muur above Sadow and Nadd. If the spirits of Nadd and Sadow are stronger than Ajunta's (which I'm not sure of), it'd only be because they're fresher.