Baela Targaryen is the daughter of Laena Velaryon and Daemon Targaryen and the twin sister of Rhaena Targaryen. The sisters were born in Pentos after their parents wed. Baela's dragon is Moondancer, who has not been seen on the show yet. Moondancer is a young dragon and is not ready to fight in the Dance of Dragons.
Baela is betrothed to Jacaerys, her cousin and stepbrother. In "House of the Dragon," after her mother's death she is raised as a ward of her grandparents, Princess Rhaenys and Lord Corlys, at Driftmark. In "Fire & Blood," the couple are very devoted to each other, and Baela doesn't want to be apart from Jace during the war.