Why was The Mountain recast multiple times throughout Game of Thrones? The character, whose real name was Gregor Clegane, appeared in all but one season of the HBO series. The Mountain received his nickname due to his intimidating size and eventually became Cersei's lone bodyguard by the end of the series.
Ser Gregor Clegane was a deadly warrior known for his excessive use of violence. He often raided villages and took innocent people prisoner before torturing them to death. Robb Stark and his men once found the remains of 200 Northmen and Rivermen prisoners that the Mountain executed. Gregor's most memorable scene came in season 4 when he dueled Oberyn Martell in a trial by combat. Oberyn wanted to avenge his sister's rape and death at the hands of Gregor. The Mountain confessed to the killing before crushing Oberyn's skull with his bare hands.
Even though The Mountain came out victorious from the duel, he too succumbed to his injuries as Oberyn had his weapon coated in poisonous venom. Gregor was killed but due to Qyburn's experimentation, the Mountain came back to life with a zombie-like state. The character lasted until the series' penultimate episode before being finally killed by his brother, Sandor, in much-hyped fan-event Celganebowl. But not just legendary for his actions in the show, The Mountain has been recast multiple times. In fact, Gregor stands as the only character in Game of Thrones to be played by more than two different actors.
The Mountain was first played by actor and wrestler Conan Stevens in Game of Thrones' first season. He actually lobbied for a role in the show and auditioned for Khal Drogo before he won the part of Gregor. The actor appeared in two episodes but he was later recast ahead of season 2 because of scheduling conflicts. After appearing in Game of Thrones, Stevens was cast as an orc king in The Hobbit film series.
Ian Whyte (Prometheus) took over the role of the Mountain in Game of Thrones season 2. He also reprised his role as a White Walker (which he initially played in the show's debut season). Whyte has stated that it was difficult to separate his emotions while playing Gregor considering how violent the character was portrayed on-screen. Whyte still remained in the series playing Dongo, a giant in the wildling army, Wun Weg Wun Dar Wun, and a wight giant.
Icelandic strongman and actor Hafþór Júlíus Björnsson took over the role of The Mountain when the character made his return in Game of Thrones season 4. Despite multiple recastings, its Björnsson's face that most fans remember when referring to the Mountain. He portrayed Gregor during the character's most memorable scenes: Björnsson's Gregor crushed Oberyn's skull, stood by Cersei as a loyal guard (despite his decaying flesh), and finally fought his younger brother Sandor is the much anticipated Cleganebowl. The Mountain has one of the most interesting arcs throughout Game of Thrones but it's the actors behind the role that made the character truly stand out.