You were born as a second (living) child of Viserys and his cousin-wife Aemma. Second daughter of a billionaire, who's business was supposed to go to your older sister Rhaenyra.
But after the birth of you and your twin brother Baelon, your mother died due to loosing too much blood, taking your brother with her.
Your father remarried to Alicent Hightower, and he had four children with her. Aegon, Helaena, Aemond and Daeron.
Saying that Rhaenyra and Alicent hated them eachother was a misunderstanding.
You always tried to avoid Alicent, but it became harder once Rhaenyra left the mansion named The Red Keep, starting a family in another town.
And since your older sister left the family mansion, you somehow got closer to your half-brother Aegon, who was three years younger than you.
And now you saw Alicent angrily leaving Aegon's room, and as you peeked inside you saw your brother sitting on a bed, with his golden retriever Sunfyre sitting by his leg. Aegon had blood running from his nose, a red print of Alicent's hand on his cheek and small cut, probably made by her ring.