Rhaegal is a dragon, one of three hatched in the vast plains of Dothrak, in the arms of Daenerys Targaryen. She gave him this name as a tribute to her older brother Rhaegar, whom she never knew. He is distinguished by his green scales.
Given to Daenerys with her brothers, Drogon and Viserion, by Illyrio Mopatis at her wedding to Khal Drogo, she accepts them, and the eggs are stored in the Khal's tent, Illyrio having said that they had turned to stone over time.
Viserys, Daenerys' brother, tries to steal them, but Jorah Mormont prevents him from doing so, as they have been given to Daenerys.
After Drogo's death, she has the three eggs placed next to his body on the funeral pyre, and sets fire to them and enters the inferno. The next day, the blaze is extinguished, she is unharmed, and the eggs have hatched. She gets up, with Rhaegal in her hand and the other two baby dragons.
Daenerys learns to train them by making them breathe fire when she says "Dracarys". She is no longer obliged to feed them, as they hunt alone near the city of Qarth, where she is staying.
Later, the dragons are stolen by Pyat Pree, and locked up in the Hotel des Nonmourants. He has chained them there, their presence increasing his magical powers. Daenerys goes there and is chained in turn. However, she says "Dracarys" and the three dragons spit flames, which kill Pyat. However, her magic survives.
She then leaves the city after locking up the self-proclaimed king, the dragons around her.
On the journey to Astapor, he and his brothers fly around the ship. When Daenerys promises the Master of the Unsullied a dragon, he chooses Drogon, the strongest of the three. Rhaegal and Viserion see him burn the Master alive, under the orders of their mistress.
In Yunkai, he stays near Daenerys on a perch during her meeting with Razdal mo Eraz. After the liberation of the city, the three dragons are laid at Daenerys' feet and she tells them to fly away.
Rhaegal and the other two dragons are released in Yunkai, and hunt around. They hunt mostly sheep, and even fight over one of them.
In Meereen, things go wrong when Daenerys learns that Drogon has burned a little girl alive. Finding the dragons dangerous to her subjects, she chooses to lock them up. She can't find Drogon, so Raeghal and Viserion are locked up in the catacombs of the city instead.
Daenerys goes down to see them to reassure them, but the two dragons don't trust her anymore, and try to kill her by burning her. She sees them again when she arrests the leaders of the city's major families. Her dragons are used as a warning to them. She even ends up getting angry, and pushes one of the masters forward. Rhaegal burns him, and eats him.
Giving up on this life in captivity, Rhaegal and his brother starve themselves and lose weight. When the Masters retaliate by attacking the city from the sea, Tyrion Lannister frees the two dragons to help Drogon burn the attackers.
To soften them up, he tells them a little story about how he wished he had a dragon when he was a boy. He tells them that at the time, everyone told him that they were gone. Less hostile, the dragons let themselves be untied, and destroy the entrance to their prison. They see Drogon flying, and join him in destroying the Masters' army.
After the new alliance with Yara Greyjoy, Daenerys has enough ships to begin her conquest of Westeros. As she stands proudly on the deck of the main ship, the three dragons fly around the fleet, roaring to announce a bloody war.
After arriving at Peyredragon, Rhaegal stays behind and flies over the island. He does not accompany Daenerys Targaryen and Drogon during the Destruction of the Spoils of Highgarden, but he goes Beyond the Wall with them and Viserion.
He spits fire on the spectres to protect the team that went to capture one. After Viserion's death and returning to the Wall, he mourns with Drogon, the death of his brother.
During the Talks in King's Landing, he accompanies Daenerys and Drogon. Unlike Drogon, he stays in the air and leaves with his brother after he drops Daenerys off.
When the Targaryen army arrives in Winterfell, Rhaegal and Drogon fly over the city.
Days pass and Daenerys worries that they are not getting enough to eat. Accompanied by Jon, she goes to see them. She tells Jon that the dragons don't like the North. She rides Drogon and invites Jon to ride Rhaegal.
Jon, who is not very sure of himself, and as soon as he is settled, Rhaegal takes off. After a few flaps of the wings, Jon becomes more confident and leads him to a waterfall. Deanerys follows him. Jon descends then Rhaegal and Drogon watch the two lovebirds kissing.
Before the battle against the Dead, Rhaegal flies over Winterfell with Drogon. Their role, along with their masters, is to stand on a high point away from the castle to get a bird's eye view and go protect Bran. After the lost Dothraki attack, Daenerys is worried and leaves with Drogon.
Jon follows her with Rhaegal. They each spit the flames of their dragon on the spectres. Rhaegal starts a second passage and Jon notices the White Walkers at the edge of the wood. But an icy fog disturbs them. Jon manages to get away a little and spit Rhaegal back at the specters. The fog hinders the dragon, forcing him to rectify his flight when he hits the trees.
Jon struggles to stay on my mount. Unfortunately, Rhaegal hits Drogon and Jon nearly falls. Jon takes Rhaegal to land near the Sacred Grove. The Night King arrives on top of them with Viserion. Rhaegal goes after them, followed by Drogon. They climb to the top of the storm and then don't see him anymore. Suddenly, Rhaegal dodges Viserion's blue flames and attacks Drogon.
The maneuver has destabilized Rhaegal but he goes back on the hunt and intercepts them. Rhaegal and Viserion grab each other and slam into each other while spinning in the air. Rhaegal suffers several injuries. Jon dodges a few blue flameballs. Rhaegal knocks down the Master of the Dead by grabbing Viserion by the neck with his claws. Jon holds on.
The dragon wounds his opponent one last time and makes it to the ground in a dangerous landing. Jon is thrown to the ground and slides on the snow. Rhaegal remains on the ground.
After the battle, he comes out with a torn wing. Daenerys comes to see how her dragons are doing. Rhaegal tries to take flight, but with difficulty. After a few flaps of his wings, he manages to stabilize and adjust to his injury.
Reclaiming the Iron Throne becomes the priority again, Rhaegal flies with Daenerys and Drogon to Peyredragon. But they are attacked upon arrival by Euron Greyjoy, who has equipped his ships with scorpions. Several bolts hit Rhaegal, one in the chest and the last one piercing his neck. He falls into the ocean.