Jacaerys Velaryon

Jacaerys was born in 114 AC (years after Aegon's conquest) to then-Crown Princess Rhaenyra Targaryen and her husband Laenor Velaryon, who is also her second cousin and thought by many to be more fond of men than women. Laenor wanted to name the child "Joffrey" after his late friend and secret lover Ser Joffrey Lonmouth, but his father Lord Corlys Velaryon overrules him and the child is instead given a "traditional Velaryon name". By royal decree, Jacaerys and his younger brothers Lucerys and Joffrey are presented with dragon eggs, with Jacaerys naming his hatchling Vermax. Jacaerys is described as a "strapping boy" who, like his brothers, had dark hair and eyes, leading to rumors that Harwin Strong, the heir to Harrenhal and a sworn shield of Princess Rhaenyra, was the boys' true father. As a result of the speculation, Jacaerys becomes very protective of his family as he grows into a "handsome teenager" who is further described as "bold", "responsible", and "politically savvy" despite his relative young age.

When Jacaerys is four years old, Rhaenyra betroths him to his second cousin Baela Targaryen, the daughter of his great-uncle Daemon Targaryen with his late aunt Laena Velaryon (Laenor's sister), the latter of whom died during an obstructed labor. After Laenor's death, the newly widowed Rhaenyra marries the also-widowed Daemon, and they have two more sons Aegon (the Younger) and Viserys, who have the Targaryen white hair unlike their Velaryon half-brothers. Since a very young age, the three Velaryon brothers became bitter rivals with their half-uncles Aegon (the Elder), Aemond and Daeron Targaryen, who were born to Queen Alicent Hightower, the second wife of King Viserys (Jacaerys' grandfather), and thus can potentially challenge Rhaenyra's claim to the Iron Throne. Alicent's parental family, House Hightower of Old Town, are also a wealthy and ambitious clan who want to seize control of royal politics, so Alicent's children also resent the Velaryon boys (whom they have mocked as "Strong boys") for obstructing their claim to the Iron Throne. Aware of this threat, Jacaerys has served as a squire in order to become more skilled in combat, presumably under his stepfather Daemon, although Harwin has also trained the Velaryon brothers before he died in a suspicious fire at Harrenhal.

When Jacaerys is fourteen, his grandfather King Viserys dies and House Hightower, in collaboration with Ser Criston Cole of the Kingsguard and other conspirators, exploit the opportunity to install Aegon the Elder (who is initially unwilling) to the throne as King Aegon II, thus usurping Rhaenyra's legal birthright as Viserys' chosen successor. This leads to Rhaenyra, who is away from the capital King's Landing due to pregnancy, miscarrying a stillborn daughter upon hearing the news. Compounding anger with the grief of losing a child, Rhaenyra crowns herself as the rightful Queen of Westeros, and a war of succession breaks out between her supporters, also known as the Blacks, and those supporting Aegon and House Hightower, known as the Greens. Because both sides have dragonriders, this Targaryen civil war is also known as the "Dance of the Dragons". At her formal coronation, Rhaenyra formally names Jacaerys as the Prince of Dragonstone and her heir to the Iron Throne.

The war initially starts with a diplomacy contest, with both sides trying to win over allegiances of various great noble houses via letters of lobbying and bargaining. As Rhaenyra's only young adult children, Jacaerys and Lucerys volunteer to be her envoys, arguing that they can travel much faster flying on dragonback and their status as princes persuades better in person, and she allows them on the condition that they avoid engaging in any battles. Jacaerys is given the more strenuous mission of visiting and winning over the Vale and the North, which he completes very successfully and personally securing a Pact of Ice and Fire with Lord Cregan Stark. It is also rumored that Jacaerys falls in love and secretly marries Cregan's bastard sister Sara Snow while in Winterfell, although Archmaester Gyldayn (who recorded the war's history) disputes and dismisses the tale as "fevered imaginings".

Jacaerys returns from his northern diplomatic mission only to find that his brother Lucerys was murdered during the southern envoy to the Stormlands and his grandmother (Corlys' wife) Rhaenys Targaryen was also killed in combat at Rook's Rest, both at the hands of Aemond riding Vhagar, the largest and most formidable dragon at the time. Due to Rhaenys' death, Corlys becomes estranged from Rhaenyra, but Jacaerys reconciles them by having Corlys named as Hand of the Queen, and he takes over the mantle of the Blacks' command. As the war intensifies, the Blacks are at an disadvantage due to having already lost two dragons and their riders, Daemon being away at Harrenhal to rally support from the Riverlands, and Rhaenyra being too valuable and also too traumatized with grief to participate in combat. With only himself and his betrothed Baela remaining and capable of fighting, and neither of their dragons big enough to challenge Vhagar, Jacaerys proposes the "Sowing of the Seeds", drafting anyone believed to potentially have Targaryen blood to attempt bonding with the unclaimed dragons at Dragonstone. This results in the recruitment of four lowborn dragonriders that significantly boosts the Black's aerial battle power, who are collectively known as "dragonseeds" or simply "the Seeds":

• Addam of Hull (who, along with his brother Alyn, are suspected to be actually Corlys' bastards), a shipwright who bonded with Seasmoke, the dragon of the late Laenor Velaryon;
• Hugh Hammer, a blacksmith who bonded with Vermithor, the dragon of the late King Jaehaerys Targaryen (Rhaenyra's great-grandfather) and the largest dragon beside Vhagar;
• Ulf White, a man-at-arms who bonded with Silverwing, the dragon of the late Queen Alysanne Targaryen (Rhaenyra's great-grandmother), and;
• Nettles, a homeless thief girl who bonded with an untamed wild dragon on Dragonstone nicknamed Sheepstealer.

To protect the safety of his remaining brothers, Jacaerys also arranges for them to be sent away from Dragonstone, with Joffrey being sent to Gulltown accompanied by Rhaena Targaryen (Baela's twin sister), and Aegon the Younger and Viserys to Pentos. However, the convey carrying Aegon and Viserys to Pentos encounters the massive Triarchy mercenary fleet, who are hired by the Greens to break the Velaryon sea blockade. The two princes' ship is attacked and sacked with Viserys lost at sea and presumed dead (in reality, he is captured and sent to Lys as a hostage), and only Aegon manages to escape atop his young dragon Stormcloud, which died of injuries upon returning to Dragonstone. Upon hearing about the incoming enemy fleet, Jacaerys leads the four new dragonriders into combat at the ensuing Battle of the Gullet. The five Blacks dragons lay waste to the Triarchy fleet, but Vermax is wounded during the fight and is pulled down by a grapnel from a sinking galley. Jacaerys is able to free himself from his drowning dragon, but is shot and killed by crossbow bolts and sinks into the sea.^[1][2]

Jacaerys' death is a huge blow to the Blacks, as Rhaenyra is further distraught by his death and so consumed with vengeful rage that she can no longer judge soundly. She later falls out again with Corlys and imprisons him, causing the remaining Velaryon fleet to abandon their blockade. Without Jacaerys leading and overseeing the recruited dragonriders, Hugh Hammer and Ulf White later betray their post and defect to the Greens, leading to the Blacks' devastating loss at Tumbleton. However, Jacaerys' prior efforts in winning over northern allies eventually pays off for the Blacks. The Winter Wolves led by Lord Roderick Dustin, a vanguard of 2,000 elderly northmen that Cregan Stark has sent in haste as the North is not yet ready for a full mobilization due to harvest, proves crucial in turning the tides of land battles for the Blacks following a series of previous setbacks. Later even after Rhaenyra's capture and execution by Aegon II, Cregan still honors his friendship and promise to Jacaerys by personally marching 20,000 troops south in support of Rhaenyra's then-only known surviving son Aegon, who is a hostage in captivity under the Greens. This new northern army, along with fresh reinforcements from the Vale, are instrumental in coercing the Greens' eventual unconditional surrender and Aegon II's assassination by poisoning at the hands of his own Greens supporters, and Cregan also assumes a brief unpaid tenure as the Hand of the King (known as the "Hour of the Wolf") to ensure the ascension of Jacaerys' brother as King Aegon III.

Collett's performance as Jace has been praised by critics. Reviewers praised the scenes of grief between Rhaenyra and Jace in "A Son for a Son", where they emotionally reunite following the death of Luke, with Katie Doll of CBR writing, "both D'Arcy and Collett are monumental examples of actors who impress in their breakout roles."^[14] James Hunt of Screen Rant referred to him as the "emotional core" of the season two episode "The Red Sowing", and lauded his scenes with Emma D'Arcy, writing, "a lot of praise must also go to Harry Collett, who gives his best performance yet as Jace: the scene where he talks about being Harwin Strong's son is powerful and devastating."^[15] Daniel Roman of Winter is Coming called the scenes in "Salt and Sea, Fire and Blood" where Jace convinces Ser Laurent to lock up Rhaenyra and his later conversation with Baela as "Harry Collett's two best scenes of the entire series".^[16]

Following the airing of their season two scene together, fans began shipping Jace and Cregan Stark together in memes, edits, and fanfiction.^[17] Tom Taylor, who plays Cregan, joked, "'Brokeback Winterfell.' I've seen that one going around, I think it's brilliant. Fans, they're going crazy with stuff. I think it's so cool that people are so passionate and want to get involved. I saw a video the other day where they stuck my head and Harry's head on these guys dancing, some AI dancing and stuff. It was ridiculous, but it was so funny."^[11] Collett later also commented on the phenomenon at the season three premiere stating, "I get shipped with Cregan Stark a lot which I find quite funny, and me and Tom laugh about that. I think the thing is called 'Brokeback Winterfell' or something."^[18]