Nine for Mortal Men doomed to die

Originally Posted by Galin

[i]'They were by far the most powerful of his servants, [/indent]

If that were the case, then the Balrog I guess does not count as a servant of Sauron? Also, what about the Mouth of Sauron - wasn't he on a similar level of power to the Witch King? There is a possibility that, being a lieutenant, he could have been of a higher rank than the Black Captain of Mordor.