Jaehaerys Targaryen son of Aegon II Targaryen

Jaehaerys was born in 123 AC in King's Landing, barely a year after his parents' wedding, arriving alongside a twin sister, Jaehaera. His father's supporters at King Viserys I's court welcomed the birth as proof that Prince Aegon already had heirs of his own. A dragon's egg was placed in his cradle, as in Jaehaera's, and both hatched: Jaehaerys's became the dragon Shrykos. That same year two of the prince's bastard half-siblings were born, one to a prostitute from Silk Street and another to a servant of his grandmother, Queen Alicent Hightower. In 127 AC his legitimate brother, Maelor, arrived.

Jaehaerys was born larger and sturdier than his twin sister, with six fingers on his left hand and six toes on each foot.

In 129 AC, Jaehaerys, his sister Jaehaera, his brother Maelor, and their mother Helaena visited their grandfather, King Viserys I, in King's Landing. There the boy heard a tale the king invented about Jaehaerys's own great-great-grandfather, King Jaehaerys I Targaryen, and how he had flown beyond the Wall to fight wildlings, giants, and wargs. That same night, Viserys I died in his sleep.

With Viserys I dead, the court at King's Landing crowned Aegon II king, while at Dragonstone Queen Rhaenyra Targaryen, Aegon's elder half-sister and Viserys's named heir, had herself crowned in turn. The realm split between greens and blacks, and the war remembered as the Dance of the Dragons broke out. As the son of the king crowned in the capital, six-year-old Jaehaerys became heir to the throne. Soon after the fighting began, his uncle Aemond Targaryen killed Prince Lucerys Velaryon, Rhaenyra's second son, and her husband, Prince Daemon Targaryen, swore vengeance with the vow "an eye for an eye, a son for a son."

Daemon's threat was carried out when two men, remembered as Blood and Cheese, broke into the chambers of the dowager queen Alicent Hightower in the Tower of the Hand. Helaena had brought her three children to visit their grandmother that night, as she often did, and once she entered with them, Blood barred the door and killed her guard while Cheese held Maelor. The intruders claimed to be debt collectors and demanded Helaena choose which of her children should die; she offered herself instead, but they refused. Warned that Blood would soon tire of waiting and force himself on Jaehaera, a weeping Helaena named her younger son, Maelor. Cheese told the boy his mother wanted him dead, then smiled at Blood, who beheaded Jaehaerys in his place with a single stroke. The two men fled with the prince's head, leaving the rest of the family unharmed.

Blood was caught at the Gate of the Gods with Jaehaerys's head hidden in a saddlebag, and before dying under torture confessed he had been heading to Harrenhal to collect his reward from Prince Daemon. Cheese was never found, and a furious King Aegon II ordered every ratcatcher in the city hanged. Helaena sank into a deep depression from which she never recovered, and the deaths of Lucerys and Jaehaerys hardened a war in which neither side was willing to show mercy.