Who wins in House of the Dragon? The answer has been sitting on bookshelves since 2018
House of the Dragon adapts Fire & Blood, which George R.R. Martin published on November 20, 2018. The end of the Dance of the Dragons has been public information for eight years. HBO is just taking its time.
Spoilers for the book and, by extension, season 4.
Both claimants lose
Rhaenyra dies first. She loses King's Landing to a rioting population, sells her crown to fund passage back to Dragonstone, and arrives to find that Aegon II has quietly retaken the island. He has his half-sister burned and eaten by Sunfyre in front of her youngest son. Aegon II then rules for a matter of months, badly maimed and out of allies, with Cregan Stark's Northern army marching south. He's found poisoned in his litter.
So the man who outlived Rhaenyra held the throne for less than a year and never got to enjoy it.
The actual winner
Aegon the Younger — Rhaenyra and Daemon's son, kept alive throughout as Aegon II's hostage — is crowned Aegon III. He's around ten. To close the war, he marries Jaehaera Targaryen, Aegon II's surviving daughter, joining the two branches on paper.
That marriage doesn't produce an heir; Jaehaera dies young and Alicent's line ends with her. Aegon III reigns 26 years, presides over the death of the last Targaryen dragon, and dies of consumption at 36. His son takes over as Daeron I, and the dynasty limps on toward Aerys II and everything Game of Thrones covers.
What it costs to get there
By the end of the Dance, Daemon and Aemond have killed each other over the Gods Eye, taking Caraxes and Vhagar with them. Sunfyre dies of the injuries he took eating Rhaenyra. A King's Landing mob storms the Dragonpit and kills five more dragons, Rhaenyra's Syrax included. Both Rhaenys and Jacaerys are already gone. Aegon III grows up too frightened of dragons to go near one.
How much of this will the show actually keep?
Fair question, because House of the Dragon has been rewriting Fire & Blood freely — season 3 alone reworked deaths, timelines, and who swings the killing blow. The broad shape is fixed by the source, but the route there has already diverged more than once.
Season 4 is the final season and is currently aimed at 2028, which gives everyone plenty of time to reread the book and argue about it. Team Black technically takes the throne. Nobody involved would describe it as a win.