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  ===Casting===
  Pedro Pascal plays Oberyn Martell.
  The fourth season adds previously recurring actors Gwendoline Christie (Brienne of Tarth), Iwan Rheon (Ramsay Snow), Kristofer Hivju (Tormund Giantsbane) and Hannah Murray (Gilly) to the series' main cast.  Iain Glen's credit is moved last in the rotation and given the "With" moniker.
  Prince Oberyn Martell, nicknamed "The Red Viper", is played by Chilean-American actor Pedro Pascal. "This was a tough one", said showrunners David Benioff and Dan Weiss about the casting. "The Red Viper is sexy and charming, yet believably dangerous; intensely likable, yet driven by hate. The boys love him, the girls love him, and he loves them all back. Unless your last name is Lannister. We found a fellow who can handle the job description and make it seem effortless. He wasn't easy to find and he won't be easy to stop". Martin commented on the casting by saying: "I wasn't present for Pedro Pascal's audition, but I understand that he really killed it with his reading. And since his casting was announced, the producer of another TV show on which he appeared recently has written me to say how terrific Pascal is, and to congratulate us on the casting. So I suspect that he will turn out to be a wonderful Red Viper". Actress Indira Varma was cast as Ellaria Sand, Prince Oberyn's paramour.
  Roger Ashton-Griffiths joins the cast in the role of Mace Tyrell. "The lord oaf of Highgarden", as his mother describes him, is otherwise known as father to Margaery and Loras. His casting was confirmed by George R. R. Martin, who introduced the actor as the solution to a riddle he'd set fans with the following message, "Yes, it's the fine British character actor Roger Ashton-Griffiths, who has been cast in the role of Mace Tyrell, son to the Queen of Thorns, and father of Loras and Margaery".
  Mark Gatiss plays Tycho Nestoris, a representative of the Iron Bank of Braavos, to whom the Iron Throne owes millions in borrowed gold. The role of Hizdahr zo Loraq is played by young British actor Joel Fry. Hizdahr is the young scion of an ancient Meereenese family who crosses paths with Daenerys Targaryen in Meereen. Elizabeth Webster was cast as Fat Walda Frey. Walda Frey is a granddaughter of Lord Walder Frey. She is the new wife of Roose Bolton, the Lord of the Dreadfort. During the wedding feast of Edmure Tully and Roslin Frey, Lord Bolton recounts to Catelyn Stark and Ser Brynden "Blackfish" Tully how Lord Walder Frey proposed him to marry one of his granddaughters and offered her weight in silver as dowry. Lord Bolton then adds he chose the fattest bride available and she has made him very rich.
  Paola Dionisotti and Rupert Vansittart were cast as Lady Anya Waynwood and Bronze Yohn Royce. They are the heads of House Waynwood and House Royce of Runestone: two powerful vassal houses of House Arryn. Yuri Kolokolnikov plays Styr: One of Mance Rayder's lieutenants and the Magnar – the name of the first ever Lord of Thenn which is now a title – of the Thenn people, a wildling clan. Two mysterious characters from Bran's storyline have also been cast: the Three-Eyed Crow, who is played by Struan Rodger, and a Child of the Forest, played by Octavia Alexandru.
  Roles that were recast for season 4 include Michiel Huisman as Daario Naharis. Huisman replaces Ed Skrein, who portrayed the character in season 3. Dean-Charles Chapman plays the role of Tommen Baratheon, King Joffrey's younger brother. Tommen was played by Callum Wharry in seasons 1 and 2. Chapman appeared as Martyn Lannister in two episodes of season 3 ("Walk of Punishment" and "Kissed by Fire"). Hafþór Júlíus Björnsson was cast as Ser Gregor Clegane, called "The Mountain". Hafþór replaces Ian Whyte, who portrayed the character in season 2.
  After an absence of at least a season, Owen Teale returns as Alliser Thorne, Kate Dickie as Lysa Arryn, Dominic Carter as Janos Slynt, Tony Way as Dontos Hollard, Andy Beckwith as Rorge, Gerard Jordan as Biter, Andy Kellegher as Polliver, Lino Facioli as Robin Arryn and Brian Fortune as Othell Yarwyck.