Ser Gregor “The Mountain” Clegane will be making an appearance on tonight’s episode of Game of Thrones, “Mockingbird.” The Mountain is one of the most imposing and feared characters in all of Westeros, but he has existed mostly on the outskirts of Game of Thrones‘s main narrative so far. Here’s a refresher on what it is that make Sandor Clegane so terrifying, including some spoilers from the books that shed some light on other parts of his histoy.The Mountain, so called because he is generally regarded as the largest man in Westeros, is the older brother of Sandor “The Hound” Clegane and the head of House Clegane. He and his brother do not get along. When they were children, Gregor gave Sandor the burn scars that cover half of his face by holding his head to a fire after he played with some of Gregor’s toys without asking permission.Gregor once had a sister as well, but she died under mysterious circumstances, as did his father and several of the servants at House Clegane. It is believed that Gregor killed them himself, for one reason or another, and that House Lannister had it covered up.During Robert’s Rebellion, The Mountain fought for House Lannister. He a reputation for fierceness in battle and being willing to use extreme violence against opponents, defeated or otherwise. During the Sack of King’s Landing, The Mountain found, raped and killed Elia Targaryen – the wife of Rhaegar Targaryen – after bashing her son’s head against a wall and having one of his men kill her daughter. Elia was the sister of Oberyn Martell and he has not forgotten this crime or the fact that it went unpunished.Gregor made his first appearance in Game of Thrones at the tourney held to honor Ned Stark as the new Hand of the King. During the tournament, he kills his first opponent then loses to Ser Loras Tyrell because Loras rode a mare in heat to distract Gregor’s horse. The Mountain becomes so angry that he decapitates his own horse with his sword and then proceed to attack Loras. Sandor Clegane steps in to stop Gregor and, eventually, King Robert orders Gregor to stand down, which he does begrudgingly.When Catelyn Stark takes Tyrion Lannister captive because she believes he attempted to kill Bran, Tywin Lannister sends the Mountain into the Riverlands to cause trouble. Word reaches the capital and Ned Stark strips the Mountain of titles and sends Berric Dondarrion to bring him in for justice. When Berric finally does catch up the Mountain, the Mountain kills him.Gregor continues to raid the Riverlands while Tywin Lannister sets up base at Harrenhal. Following what Tywin believes is an assassination attempt on his life, he returns to the Westerlands and leaves the Mountain as castellan of Harrehal. He doesn’t last long in the role as he is forced to abandon the castle when Robb Stark’s army approaches, but only after executing the 200 prisons housed at the castle and leaving them to rot. Last we heard, he was still in the field making trouble wherever he went.Game of Thrones, “Mockingbird,” airs Sunday night at 9 PM ET on HBO
