House of the Dragon, the long-awaited prequel to Game of Thrones, just began releasing episodes on HBO Max, and has become the highest-watched premiere in the streaming service's history. Though many fans were frustrated by the final season of Game of Thrones, the cultural force that it had been prior to that season seems to have been enough to bring fans back.
House of the Dragon is based on George R. R. Martin's Fire & Blood, which details the history of House Targaryen. The series picks up with the book's twelfth chapter, "Heirs of the Dragon: A Question of Succession," and will continue through the chapters detailing the Targaryen Civil War known as the "Dance of Dragons." While many of the historical details have been consistent with the book, some characters' appearances deviate significantly from their literary counterparts. Though few characters are described in much detail, their overall appearance does become increasingly significant as the conflict rises and the legitimacy of each character's lineage is put to the test.
Lyonel Strong
Lyonel Strong is the Master of Laws for King Viserys when the series begins, and his son Ser Harwin Strong is destined to have a significant role in the future. Lyonel is described in the books as being "a big man, burly and balding," and his son is described as having inherited his size.
Though his specific features are not mentioned, characters that are suggested to be his grandsons are tied to the family by their features: "brown hair, brown eyes, and a pug nose.” Actor Gavin Spokes fits the descriptions for House Strong in general, though he doesn't have the hair loss of his book counterpart.
Laena And Laenor Velaryon
Laena and Laenor Velaryon are incredibly important in the earliest succession questions in Fire & Blood, as the children of Princess Rhaenys, who had a strong claim to the throne. Because of this, they end up being major figures when it comes to establishing future claims. At the time of Aemma's death, Laena should be 12 and Laenor 11, which fits fairly well with child actors Nova Foueillis-Mosé and Matthew Carver.
Laenor is described as having "the aquiline nose, silver-white hair, and purple eyes that bespoke his Valyrian blood," and Laena has "a great mane of silver-gold ringlets that fell down past her waist." Though Targaryens have broadly been described as having pale skin, there is no mention of their skin color in the book, which has been the source of some controversy in the fandom. Furthermore, House of the Dragon seems to be continuing Game of Thrones's choice to discard the Targaryen's purple eyes, although their hair color is maintained.
Ser Criston Cole
Fans got their first glimpse of Criston Cole in the premiere of House of the Dragon, where he defeated Daemon Targaryen in the Heir's Tournament. He is revealed to have Dornish ancestry (which was not mentioned in the books), and is largely seen as an unknown entity, since he is not connected with the established nobility of Westeros.
He is 23 when he comes to [King's Landing]—25 at the time of Queen Aemma's death—and is described as having "pale green eyes, coal black hair, and easy charm." Actor Fabien Frankel fits the description well enough, though his eyes are brown and he is a few years older than Criston would have been at his introduction.
Mysaria
Mysaria is introduced early on in Fire & Blood as Daemon Targaryen's mistress. A former slave from Lys, she became his lover and also his trusted ally, providing him with information and services around the city.
Though most of her features are left up to the imagination of the reader, she is described as having "skin as pale as milk" and potentially very fair hair which led to her nickname—Misery, the White Worm. The show changed this trait, casting Japanese-born actress Sonoya Mizuno for the role, and keeping her natural coloring. While the character may look different than fans expected, there's no doubt she'll have the proper attitude for the role.
Lord Corlys Velaryon
Corlys Velaryon is a powerful seafarer known as the Sea Snake, who serves as Viserys's Master of Ships. He is married to Princess Rhaenys Targaryen, and their children end up being the subject of several succession debates.
He is 52 years old when Queen Aemma dies, but that is the only thing that can be said for certain. His children have Valyrian features, which presumably come from both himself and his wife, but the specifics are open to interpretation. Actor Steve Toussaint is 57 years old, which will serve him well as the show moves through time, and is portrayed with the light blonde hair typical of House Velaryon.
Princess Rhaenys Velaryon
Rhaenys Velaryon is a force to be reckoned with, pushing for her (and her children's) claim to the throne to be recognized over Viserys's in the Great Council of 101 AC. She would have been 27 at the time of the Council and 31 when Queen Aemma died.
Despite being born a Targaryen, Princess Rhaenys is described as having black hair, which becomes streaked with white as she ages. This trait was changed for the series, where she has the traditional silver hair of the Targaryen line, and she was aged up, with actress Eve Best being 51, to pair better with Corlys.
Prince Daemon Targaryen
Daemon Targaryen is the younger brother of Viserys and presumptive heir to the throne at the beginning of the series. His appearance is rarely mentioned, except that he was "lean and hard," as well as being "dashing," but it can be assumed that he had the standard Targaryen features.
At the time of Queen Aemma's death, Daemon should have been around the age of 24, far younger than Doctor Who actor Matt Smith's 39 years. This age change was likely made to prevent the need for multiple actors as the in-world years pass by.
Alicent Hightower
Alicent Hightower is the daughter of Otto Hightower, Hand to the King, and her role in Court becomes increasingly more significant as time goes on. House Hightower proves itself incredibly influential, but neither Alicent nor her father's appearance is described in any depth.
In the book, Alicent is 17 when Queen Aemma dies, which is relatively well-matched by her 19-year-old actress, Emily Carey. She may have similar features to the Targaryens, as King Jaehaerys occasionally mistook her for his daughter Saera, but her most identifiable traits are that she remains "slender and graceful" as she ages, rather than losing her youthful beauty.
King Viserys Targaryen
Except for the brief prologue to the show that features the Great Council of 101 AC, Viserys Targaryen is the undisputed king of Westeros when the story begins, though he is struggling to determine the future line of succession. He was 26 years old when he ascended the throne and was 28 by the time Aemma died.
There is very little description of Viserys's features, although he presumably had the traditional Targaryen silver hair and purple eyes. As years went on, he gained weight and developed several health conditions: "gout, aching joints, back pain, and a tightness in the chest.” Like many other characters, Viserys is played by a considerably older actor than his character would have been at the start, with Paddy Considine being 48 years old.
Princess Rhaenyra Targaryen
Rhaenyra is probably the character that looks the least like her book counterpart, despite having the standard Targaryen coloring. While the younger actress cast to play the role (Milly Alcock) is 22 years old, Rhaenyra would have been only 7 or 8 when her mother died and she became the heir to the throne. Rhaenyra was known as "the Realm's Delight," and is said to have been "a precocious child, bright and bold and beautiful as only one of dragon’s blood can be beautiful."
Rhaenyra is described as having "grown stout and thick of waist" by the time she is around 20, a description which continues into her 30s, when she will be played by 30-year-old non-binary actor Emma D'Arcy. While fans may be disappointed to learn that they have been deprived of plus-sized representation in adult Rhaenyra, Emma D'Arcy otherwise appears to be a tremendous fit for the role.