Syrax was the yellow she-dragon of Rhaenyra Targaryen and had no other rider: the princess claimed her in 104 AC at the age of seven, when the dragon was still young, and named her for a goddess of old Valyria. She grew huge and formidable, though she was kept in chains and exceedingly well fed, and by the time of the Dance of the Dragons she had not hunted in years and had none of Caraxes's experience of battle. She laid several clutches of eggs in the reign of Viserys I, Caraxes believed to be one of her mates, and from an egg of her last clutch, given to Rhaenyra's stepdaughter Rhaena, the dragon Morning was hatched.
Rhaenyra could not fly for a time after the stillbirth that opened the war, but she rode Syrax at the taking of King's Landing, and there the dragon was chained in a horse stable in the outer ward of the Red Keep while the other black dragons went to the Dragonpit. When the mob stormed the pit in 130 AC, Prince Joffrey Velaryon tried to ride Syrax to the rescue of the dragons there, and she threw him from her back to his death in mid flight. Drawn by the blood, she flew to the Hill of Rhaenys and, rather than burning the mob from the air, came down among them, killing dozens with tooth and claw until she was slain on the ground; the accounts of who dealt the killing blow contradict one another.