
Vhagar was a destructive, quarrelsome and aggressive creature all her life, even for a dragon.

It is said that Meleys was one of the few dragons who could match Vhagar in combat, despite the latter being a hardened and pitiless survivor of a hundred battles. She was said to have been as big as Balerion himself was, and only Vermithor, the Bronze Fury, was close to its size. By the time of the Dance of the Dragons, and the deaths of Balerion and Meraxes, Vhagar was one of the largest dragons in existence. During the War of Conquest, she was already a huge and ferocious dragon. None of Vhagar's colours are explicitly mentioned, not even her flame. Vhagar was ridden by Visenya Targaryen, Laena Velaryon and Aemond Targaryen. It was named for one of the gods of old Valyria. Alicent fears that Rhaena’s dragon egg hatching means the blacks will be seen as more legitimate than the greens, but Morning was still too young to be ridden during the fighting.Vhagar was one of the dragons used by Aegon The Conqueror and his sisters during The War of Conquest.

Martin’s Fire & Blood explains that the news of Morning’s birth troubles the greens, who had already lost most of their dragons in the Targaryen civil war. Rhaena will eventually be bonded with the dragon Morning, who will hatch from an egg after the Dance of the Dragons has already begun. Despite not being able to mount her mother’s old dragon, Rhaena Targaryen will still become a dragonrider in House of the Dragon. Following Laena Velaryon’s death, Vhagar was kept at Driftmark so that Rhaena would have the opportunity to claim her mother’s dragon as her own, but Alicent's son Aemond Targaryen stole her away. Her parents Laena and Daemon as well as her older sister Baela all had dragons, but Rhaena’s egg failed to hatch after 8 years. Much like Aemond in House of the Dragon episode 6, young Rhaena Targaryen lamented not having a dragon of her own. The aging Vhagar won't let just anyone mount her anymore, meaning Aemond's considerable boldness was enough for the experienced dragon to let herself bond with him. House of the Dragon episode 7 saw Aemond prevail against the resistance of the strongest dragon in Westeros, with the young Targaryen even managing to stay on Vhagar’s back when she flew erratically. Aemond also proved his great bravery by sneaking away from the castle, facing Vhagar on his own, continuing to utter High Valyrian commands, and standing his ground when the mighty dragon Vhagar showed signs of aggression like breathing fire at him. The Valyrian blood of Aemond certainly played a part in his ability to claim Vhagar, but it may have also connected to the blood he shares with Baelon, Vhagar’s last rider before Laena. The reason why a dragon allows a specific person to claim them isn’t entirely clear, but has to do with their courage and worthiness as a dragonrider. Before Aemond, Vhagar was ridden by Queen Visenya (Aegon the Conqueror’s sister-wife and the wielder of Daemon's sword Dark Sister), Viserys and Daemon’s father Prince Baelon Targaryen, and Laena Velaryon, each of whom had to prove their bravery in order to claim her.

Dragons don’t easily allow new riders to claim them, especially dragons like Vhagar who are nearly 200 years old, have known several riders, and have spent many stretches of their lives roaming freely.
