Emma D’Arcy as Princess Rhaenyra Targaryen D'Arcy is set to star as Princess Rhaenyra Targaryen, who is the king's first-born, pure Valyrian-blooded child and a dragonrider. According to Variety, Rhaenyra was "born with everything . . . but she was not born a man." Image Source: Getty / David M. Benett