Xidd Orlaq was a Prince, but otherwise minor official from the world of Ecaz, whom Emperor Paul Atreides Muad'Dib granted custody of Caladan to, immediately after his ascension to the Golden Lion Throne.
Administrator of Caladan
Orlaq was a just and wise ruler, and the people of Caladan, especially Cala City, grew to like him, although they at first gave him a chilly reception. Like all of the previous administrators of Caladan, he lived in the capital on the Western Continent, in Castle Caladan.
When Paul and Jessica Atreides visited Caladan just one year into his rule, the Prince ensured that Paul and his mother were treated with great fanfare and adulation. Orlaq encouraged Paul to make Caladan the capital of all the Imperium, but it was during this visit that Paul realized he was no longer just a Duke, but Emperor of the Known Universe. Orlaq was crest-fallen when a courier arived on a heighliner and announced that Fremen Jihadi soldiers had taken Kaitain. Paul announced that he had to leave to inspect the taking of the former Corrino Empire capital; and made his mother the Duchess of the water world.
What happened to Orlaq afterwards is not known.