In the lore of A Song of Ice and Fire, Helaena Targaryen is King Viserys I Targaryen's daughter by Queen Alicent Hightower. She is married to her elder brother, Aegon, in the tradition of House Targaryen, per the wishes of their mother. House of the Dragon makes it clear from the get-go that Alicent lacks the cutthroat, Machiavellian traits that other members of House Targaryen possess.