__________________ "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
Grathan has a lot of hype and was supposedly a parallel for Dark Councillors, based on his title of "the thirteenth Dark Councillor", except it's a self-declared title from what I recall, and he got beaten by an early Warrior. He's really not that impressive.
Skotia is implied to be more powerful than Zash and destroyed his Trandoshan bodyguards effortlessly - a similar-level Inquisitor required the anti-cybernetic device to win.