The reigning family of Khionia, whose king and queen betrothed their daughter Kaira in childhood to Darem Reymi, intending him to rule the planet at her side.
The Khionian royal house features in the Starfleet Academy episode Ko'Zeine. Cadet Darem Reymi was promised as a child to his closest friend Kaira, daughter of the reigning king and queen, and has been brought up to expect that the marriage will make him king of the whole planet.
The plan had been to wait until Darem had served some years in Starfleet. After health scares the monarchs decide to abdicate early, the wedding is moved forward, and Darem is abducted from his dormitory in what proves to be a traditional Khionian pre-wedding ritual.
He goes through with the ceremony, and his fellow cadet Jay-Den Kraag gives the speech of the ko'zeine, the equivalent of a best man. Listening, Kaira understands how much of himself Darem has buried for duty's sake, and privately offers to have the marriage annulled if he abdicates, freeing him to return to the Academy.