Rhaena is Baela's twin and also the daughter of Laena and Daemon. She has lived with her father's new family since her mother's death. She is betrothed to her cousin and stepbrother Lucerys Velaryon, who will succeed their grandfather Corlys as Lord of Driftmark. In the show, Rhaena does not yet have a dragon, but she will eventually hatch and bond with the dragon Morning.
Baela and Rhaena's mother, Laena, died in childbirth, as did her baby. The pair were outraged that Aemond claimed their mother's dragon Vhagar, which they felt should have gone to them. During the Dance of Dragons, she and Prince Joffrey stay in the Vale of Arryn for their protection.