SkekNa's loyalty within the castle is to the brutish SkekUng. As with all the Skeksis, skekNa has a noble counterpart living with the Mystics. SkekNa's alter ego is the herbalist urNol.
"Between meals the Skeksis went to skekNa the Slave-Master for scraps to appease the raging hunger they always felt. SkekNa was purely and openly evil from the beginning, but without him the work of the castle would never have been done."
- The World of the Dark Crystal Pre-production notes for the Slave-Master/Executioner call for a character that "remains evilly silent most of the time, except for occasional sneers and hisses. His action is dominated by kicking, whipping, and herding little Pod slaves."
SkekNa's costume is made up of a leather surcoat covered in metal clasps, chains, manacles and padlocks, and a shiny reptile skin robe. Distinguishing features of the Slave Master include scars. Other pre-production notes state that the character "will have a hook to replace a missing hand, and an eye patch over a mucid socket."