Rhaegal is one of three dragons introduced in the novel A Game of Thrones and subsequent novels as well as the Game of Thrones television adaptation of the novels. Rhaegal was named after Daenerys Targaryen's late brother Rhaegar Targaryen.
Rhaegal hatched from one of three eggs that had been presented to Daenerys at her wedding to Khal Drogo during her husband's funeral. He along with his brothers Drogon and Viserion imprinted on Daenerys as their mother. Rhaegal had green and bronze colored scales with yellow-orange colored wings. When first hatched Viserion was about the size of a house cat but like his brothers grew to be quite large.
Along with his brothers Rhaegal was capable of breathing fire, and Daenerys trained him and his brothers to breathe fire whenever she said Dracarys (High Valyrian for Dragonfire). Pyat Pree and the Masters fleet all were on the receiving end of fire from Rhaegal and his brothers, with fatal results.