Like Game of Thrones, House of the Dragon has a lot of characters to keep up with. Thankfully, the spinoff series has a major advantage by keeping its characters condensed to House Targaryen, its few allies and many enemies. But it still might be helpful to know who is related to whom and who the major characters are before jumping into the first episode.

House of the Dragon is HBO's biggest series of 2022, and fans of Game of Thrones are anxiously waiting to see if the prequel series can stand on its own. The series takes place roughly 200 years before the events of Game of Thrones, during the height of the Targaryen dynasty in Westeros. Adapted from George R.R. Martin's Fire & Blood, House of the Dragon will portray the nasty Targaryen war of succession known as the "Dance of the Dragons." To keep track of who is who in the massive world of Westeros, take a look at the key players who will drive the series.

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Paddy Considine as King Viserys I Targaryen

house of the dragon Viserys

Game of Thrones fans might recognize the name Viserys because of Daenerys' abusive older brother. But there was actually a Targaryen named Viserys who was a king centuries before the events of Game of Thrones. Paddy Considine portrays King Viserys I, Rhaenyra's father and Daemon's brother. Like Bran Stark, Viserys was chosen by the lords of Westeros to succeed Jaehaerys I Targaryen at the Great Council at Harrenhal. He's also known as one of the kinder kings of Westeros, well-loved by lords and commoners alike. Considine is known for his roles on other television series such as Peaky Blinders and The Outsider.

Emma D'Aarcy and Milly Alcock as Princess Rhaenyra Targaryen

Rhaenyra Tagaryen, played by Emma Darcy, in House of the Dragon Season 1.

Milly Alcock will first portray a younger Rhaenyra Targaryen during her teenage years until Emma D'Arcy takes over as adult Rhaenyra. Rhaenyra is Viserys' firstborn child and is Daemon's niece. Viserys unconventionally names Rhaenyra his heir, which his brother Daemon and other lords of Westeros oppose because she is a woman. Showrunner Ryan J. Condal once described her as the most important Targaryen in the series. While having been in smaller roles in Australian TV series, this is Alcock's breakout role. D'Arcy is known for their roles in Truth Seekers and Misbehavior.

Matt Smith as Prince Daemon Targaryen

Matt Smith House of the Dragon

One of the more famous faces on House of the Dragon, Matt Smith portrays Daemon Targaryen, Viserys' brother and Rhaenyra's uncle. Daemon is a skilled warrior and dragonrider, but a complicated human being. He's bad-tempered and unprincipled, and has a rival with the Hand of the King, Otto Hightower. While initially angry about his niece being Viserys' heir, Daemon puts it aside to keep a Targaryen on the Iron Throne. Smith is most known for his roles as the Eleventh Doctor on Doctor Who and as Milo in the infamous Marvel film Morbius.

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Olivia Cooke and Emily Carey as Lady Alicent Hightower

house of the dragon alicent hightower

Just like the case of Rhaenyra, Emily Carey will start out the series as a teenage version of Lady Alicent Hightower, with Olivia Cooke taking over once the character becomes an adult. Described as the most comely woman in the Seven Kingdoms, Alicent is the daughter of the Hand of the King and is Rhaenyra's best friend. Cooke has described Alicent as a product of patriarchy and has compared her to Cersei Lannister. Carey previously portrayed the younger counterparts of Princess Diana in Wonder Woman and Lara Croft in Tomb Raider. Cooke is best known for her roles on Bates Motel and in Ready Player One.

Rhys Ifans as Ser Otto Hightower

Otto Hightower looking on in House of the Dragon

Rhys Ifans portrays Ser Otto Hightower, the Hand of the King and Alicent's father. He is faithful to both his king and the realm, and believes Daemon Targaryen is the greatest threat to the realm. However, his arrogance gets the best of him as he always tries to bend Viserys' ear to do as he says. If Ifans looks familiar to Harry Potter fans, it's because he portrayed Xenophilius Lovegood in Harry Potter and the Deathly Hallows Part 1. Marvel fans might recognize him as Curt Connors/Lizard in The Amazing Spider-Man and Spider-Man: No Way Home.

Steve Toussaint as Lord Corlys Velaryon

Lord Corlys Velaryon in House of the Dragon

Steve Toussaint is Lord Corlys Velaryon, one of the richest men in the Seven Kingdoms who also has the largest navy in the world. Known as "The Sea Snake," his adventures on the sea have made him a legend. He's married to Princess Rhaenys Targaryen and has two children: Laenor and Laena. Toussaint has spoken out about dealing with racial abuse he's received online after being cast in the role, but judging by his former roles in Prince of Persia: The Sands of Time, Doctor Who and Skins, he's the perfect choice for Corlys Velaryon.

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Eve Best as Princess Rhaenys Targaryen

Rhaenys Targaryen looking on in House of the Dragon

Labeled "The Queen Who Never Was," Princess Rhaenys Velaryon is a dragonrider and wife to Lord Corlys. Her cousins are Viserys and Daemon and was passed over as Queen of Westeros in favor of Viserys because of her status as a woman. Her great intellect would've made her a great queen, but she is truly someone who deserved better. Rhaenys is portrayed by Eve Best, who is known for her role as Dr. Eleanor O'Hara on Nurse Jackie.

Fabien Frankel as Ser Criston Cole

house of the dragon Criston cole

Outside the major houses is Ser Criston Cole, a common-born son of Dornish descent who has no land or titles, but has risen to Lord Commander of Viserys I's Kingsguard. His sword-fighting skills come in use during tourneys, one of which he defeats Daemon Targaryen in. While not directly related to the royal family, he still has a heavy hand to play in the war to come. Ser Criston is portrayed by Fabien Frankel, who co-starred alongside Emilia Clarke (A.K.A. the Daenerys Targaryen) in Last Christmas.

Sonoya Mizuno as Mysaria

house of the dragon Mysaria

Lastly, and certainly not least, is Mysaria -- portrayed by Sonoya Mizuno. Like Ser Criston, Mysaria has no land or titles but is the most trusted ally (and lover) of Daemon Targaryen. She acts as his mistress of whisperers, feeding him information from around the realm. Mizuno has had significant roles in the Alex Garland projects Ex Machina, Annihilation and Devs.

House of the Dragon premieres Sunday, Aug. 21 at 9pm ET/PT on HBO and HBO Max.