Glossu Rabban Harkonnen, also known as the Beast, Mudir Nahya (Demon Ruler), and King Cobra by the Fremen, was the older nephew of Baron Vladimir Harkonnen, and the Count of Lankiveil.

Established on Dune: He inherited the Harkonnen penchant for sadism and cruelty, but not the cunning. He was best known for his tyrannical and vastly ineffective governance of Arrakis during the Harkonnen fiefdom of Arrakis, as well as during the insurgency of the Fremen led by Paul Muad'Dib. He earned the nickname "Beast" when he killed his father, Abulurd Harkonnen. The Baron planned to let Glossu rule the planet for a time through fear and terror so that when his favored brother, Feyd-Rautha, took over, the new ruler would be welcomed as a hero.