SkekUng

SkekUng is the general of the Skeksis. He commands the Garthim which fight and hunt for the decadent Skeksis, so he's better known as the Garthim-Master. He is a stern, massive, sneering presence, and a natural leader who values anger and brute strength. SkekUng's alter ego amongst the gentle and wise Mystics is urIm, the Healer.

In the pre-production notes for the film, the Garthim-Master is "identified by the sound of his spurs striking on the castle floors and his complete lack of subtlety. The Garthim-Master enjoys tearing apart soft Gelflings for sport." The Garthim-Master is identifiable amongst the Skeksis for its rattling armor, yellow fangs, and bellowing voice.

Upon the death of the Skeksi Emperor skekSo, it is skekUng, the Garthim-Master, that feels confident that his violent strength will earn him the throne. He enjoys the support of skekTek and skekNa.

SkekUng was eventually reformatted back into UngIm, but a Heartless copy of the 2nd Emperor was created by the Mad Doctor to lead the Skeksis in the Circle of the Blot.
 * "Strongest of all for brute force, after the Emperor was skekUng the Garthim-Master. Torment was his pleasure, though his urSkeks original had been a healer and continued so in his urRu form. Hidden in that tall, shining urSkeks was one who, ages later, could find pleasure in tearing apart the gentle Gelfling. The urSkeks knew this evil was in them and tried hard to burn it out. The soul driven by strong forces is weak, and the soul without strength is helpless. Wisdom and compassion have their roots in the same soil as violence and hate; the strong being allows them to fight within him, to recognize that his strength of will must control the evil he could do. That the urSkeks did not understand this and violated their nature was the ruin of our World. They looked and spoke like superior beings, but they too were capable of error."
 * - The World of the Dark Crystal