The http://www.uesp.net/wiki/Lore:Dremora also mentions two more rankings: Narkynaz and Kyngald. A quick search reveals that they are new rankings added by ESO.
A interesting interpretation, though I wouldn't necessarily count the Feydnaz out as a lower rank because the title lacks "kyn."
Of the dremora language we know very little; but we do know that "kyn" means "the people" and that "kynaz" means "he of the people." Meanwhile "naz" or "az" simply seems to determine that we use the adjectival form of a word. Perhaps his title simply means "he of the gate" and isn't actually a real full caste. Just a job title.