King Viserys III Targaryen is a major character in the first season. He is played by starring cast member Harry Lloyd, and debuts in the series premiere. Viserys is the younger brother of the late Rhaegar Targaryen, the older brother of Daenerys Targaryen, and the paternal uncle of Jon Snow. Viserys and Daenerys are the remnants of the exiled House Targaryen following Robert's Rebellion against their father Aerys II Targaryen, the Mad King.