Dragons are mythical creatures in the "Game of Thrones" world capable of breathing fire with the command of "Dracarys", the High Valyrian word for "Dragonfire".
The Mysterious Origin of Dragons
While their origins are unknown, connections between dragons and humans were first established by the Valyrians in Essos. As a result, the Valyrian civilization prospered for ages until the Doom of Valyria.
Westeros first witnessed Dragons when Aegon Targaryen I and his sisters, Rhaenys and Visenya, conquered the seven kingdoms. Dragons diminished in number after the Targaryen civil war called the "Dance of the Dragons" and went extinct a few years later. They made a return when all three of Daenerys Targaryen's dragon eggs hatched.
The New Three Dragons
Queen Daenerys Targaryen hatched her dragon eggs on the funeral pyre of her Dothraki husband, Khal Drogo. They were named Drogon, Rhaegal, and Viserion and were the only "Game of Throne" dragons.
1. Drogon: Named after Drogo, Drogon was the personal mount of Daenerys and THE dragon in "Game of Thrones". The biggest of the original three, Drogon helped his rider win many wars both in the book and in the TV show. After Daenerys' death in "Game of Thrones", Drogon was reported to be flying east over the continent of Essos. Tyrion Lannister had a memorable encounter with Drogon.
2. Rhaegal: Named after Prince Rhaegar Targaryen, the elder brother of Daenerys. In "Game of Thrones", Rhaegal was killed with a scorpion bow by Euron Greyjoy. Jon Snow, who was revealed as Rhaegar's son and the nephew of Daenerys, also rode the dragon in the last season of the TV show.
3. Viserion: Named after Daenerys' other brother Viserys, Viserion was killed by the Night King in front of Daenerys during season 7. The Night King subsequently revived and rode him, with Viserion becoming a part of the White Walkers' army. He finally died when Arya Stark killed the Night King.