Priest-king was the title held by the theocratic ruler of the Stellan, an isolationist species that dwelled on the eponymous planet.
Sources
The Not-So Magnificent Seven on StarWars.com (backup link) (original link is obsolete) (First mentioned)
Priest-king was the title held by the theocratic ruler of the Stellan, an isolationist species that dwelled on the eponymous planet.