In the penultimate episode of House of the Dragon Season 2, Addam, Hugh, and Ulf become the riders of Seasmoke, Vermithor, and Silverwing, respectively. This has left viewers wondering which dragons are still in Westeros and have not been claimed.

As of Season 2 Episode 7, there are three unclaimed adult dragons: Grey Ghost, Sheepstealer, and Cannibal. These three are truly wild dragons, as none of them had riders for the Dance of the Dragons. In George R. R. Martin's book, the little folk of Dragonstone named all three of them based on their predominant features.

As the name suggests, Grey Ghost was a pale gray-white dragon in the book, with his color sometimes being described as that of the morning mist. Grey Ghost did not appear in the show until Season 2 Episode 7, though he was indirectly mentioned once in the Season 1 finale.

Grey Ghost is perhaps the most elusive of all the dragons in the series. If House of the Dragon follows the book in this regard, Grey Ghost will remain riderless. In the book, Addams' brother Alyn attempted to claim the dragon but failed. However, since the character doesn't seem to have any desire to be a dragon rider in the show, that may not be repeated in this adaptation.