Prince Jacaerys Velaryon (Harry Collett), aka Jace, was Rhaenyra’s eldest son. The public record states that his father was Lord Laenor Velaryon, though more likely, he and his two brothers were fathered by Ser Harwin Strong.
In an attempt to quell the rumors about their parentage, King Viserys ordered a dragon egg to be placed in each of the boys’ cradles, so they could instantly claim the dragons that hatched. Those who believed that Jace and his brothers were bastards doubted they could bond with dragons, or that the eggs would hatch at all — but they were proven wrong.
Jace’s dragon was named Vermax. He was one of the youngest dragons in Rhaenyra’s active army, and the pair didn’t see any combat for two full seasons. (However, Jace did fly Vermax to the Wall, the Vale, and the Twins to treat with Houses Stark, Arryn, and Frey, respectively.)
In the season three premiere, Jace flew Vermax into his first and last battle. The dragon was impaled and pulled into the sea. Jace survived the drowning, but when he emerged on the surface, he was shot to death by enemy arrows.