Vermax

Rhaenyra Targaryen decreed that each of her children would receive a dragon's egg at birth. Many at court doubted the eggs would ever hatch, since they doubted the children's true parentage. Young Jacaerys's egg did hatch, and the hatchling that came out of it was named Vermax.

He was a male dragon that grew at a striking pace year after year; by the time he died, at only fourteen, he had become a mount fit to carry a rider into war.

When the Dance of the Dragons split the realm in two, Jacaerys mounted Vermax and flew north. He sought to win swords for his mother's cause, and to that end he visited the Eyrie, Sisterton, White Harbor, and Winterfell, seat of House Stark.

The jester Mushroom left an account of that visit: while the prince parleyed with Lord Cregan Stark, Vermax hid away in the crypts of Winterfell, near the hot springs running beneath the castle. He was said to have laid a clutch there, though no egg was ever found, which points instead to Vermax being male.

Vermax fought in the Battle of the Gullet, one of the war's naval clashes. He flew too low over the water and crashed into the sea; the accounts disagree on why. One version tells of an iron bolt that pierced his eye, another of a grapnel that lodged between two scales and tore a ragged gash as he fought to keep flying.

He tried to take to the air again after the fall, but struck a burning galley and sank under its weight. Jacaerys managed to break free of his mount, only to be cut down by crossbowmen soon after. Vermax was fourteen years old.