Gregor Clegane

"I always thought you had a talent for violence."

- Tywin Lannister to Gregor Clegane

Gregor Clegane is a recurring character in the first and second seasons. He was originally played by guest star Conan Stevens and debuts in "Cripples, Bastards and Broken Things." Stevens was replaced by Ian Whyte for the second season. Whyte had already worked on the series in other roles.

Ser Gregor Clegane is the head of House Clegane, a minor vassal house of House Lannister. Ser Gregor is a notoriously fearsome warrior with a tendency toward extreme violence. During the War of the Five Kings he raided the Riverlands on orders from his liege lord Tywin Lannister. Ser Gregor served briefly as castellan at Harrenhal before withdrawing his troops.

Background
Ser Gregor Clegane is the head of House Clegane, a knightly house from the Westerlands, and the elder brother of Sandor Clegane, whom he despises. When Sandor and Gregor were children Gregor held his brother's face in a fire for using his toys without permission, horrifically scarring him. Gregor is a landed knight rather than a full lord. Gregor is freakishly huge, said to be the largest man in Westeros, almost eight feet in height and heavily muscled. For this reason he is called "The Mountain That Rides" or, simply, "The Mountain". He is feared throughout Westeros with a reputation for ferocity and anger. He is a loyal retainer and servant of House Lannister, particularly to Lord Tywin.

Numerous servants have gone missing at the Clegane keep over the years, apparently killed by Gregor for minor slights in one of his infamous rages, and their deaths then hushed up. Gregor's own father and sister died under dubious circumstances as well, and Sandor half-suspects that Gregor may have killed them as well. Their sister died when Sandor was too young to remember her well, and their father died years later in what was said to be a "hunting accident". Influenced by Tywin Lannister, Prince Rhaegar Targaryen himself anointed Gregor as a knight, a great honor, even though Gregor was an infamously dishonorable man.

During Robert's Rebellion, one year after Prince Rhaegar knighted him, Gregor participated in the Sack of King's Landing. He raped and murdered Rhaegar's wife Princess Elia Targaryen after killing her baby son Aegon by bashing his head against the wall, while Amory Lorch killed her daughter Rhaenys.

Season 1
Ser Gregor takes part in the tournament to celebrate Eddard Stark's appointment as Hand of the King. He kills Ser Hugh of the Vale in a joust, horrifying the crowd. Littlefinger tells Sansa Stark that Gregor burned his brother Sandor's face over a naked flame when they were boys because Sandor borrowed one of his toys without asking. He tells her that few people know the story and not to let Sandor Clegane know that she does. When Gregor faces Ser Loras Tyrell, he loses the joust because Loras chose to ride a mare that was in heat to distract Gregor's stallion. Flying into a rage, Gregor demands his sword, then decapitates his own stallion with a single swing of his sword, before the entire horrified crowd. Ignoring his surroundings, he proceeds to knock the surprised Loras off his horse, and is on the verge of dishonorably killing him, when his brother Sandor intervenes, fighting him off to protect Loras. Gregor only stops when King Robert himself shouts a demand to end his folly, at which the fuming Ser Gregor relents and leaves.

Catelyn Stark takes Tyrion Lannister into custody on suspicion of the attempted assassination of her son Bran. In retaliation Gregor is dispatched to raid the Riverlands, her homeland. Refugees from the Riverlands attend court in King's Landing and report that a huge knight who could take the head of a horse in one blow lead the attack and had sacked their villages. Littlefinger says remind you of someone. Eddard Stark sends Ser Beric Dondarrion with a hundred men to bring Gregor to justice. Eddard declares him a false knight and strips him of all ranks and titles, lands and holdings, and sentences him to death. The ruling is made moot by Eddard's arrest for treason and subsequent execution.

When Robb Stark's victory against his son forces Lord Tywin to withdraw his forces to Harrenhal, he orders Ser Gregor to take five hundred men and "set the Riverlands on fire" from the Red Fork to Gods Eye.

Season 2
Gregor continues to raid the villages of the Riverlands from the Lannister army's base at Harrenhal. His men torture the prisoners they take for information about the Brotherhood and hidden valuables. He selects the prisoners for torture personally. Ser Amory Lorch adds a group of captured Night's Watch recruits to the captives. Lord Tywin Lannister arrives during the torture and asks Gregor what is going on. Gregor says that they were not expecting Tywin for another day. Tywin asks why the prisoners are not in their cells. Gregor says that their cells are overflowing. One of Lorch's men interjects that the prisoners will not be there long. Tywin asks if they are so well manned that they can afford to discard able and skilled prisoners. He asks a prisoner if he has a trade and learns that he is a smith. Tywin orders the prisoners put to work, sparing the young man.

Following the assassination of Ser Amory just outside Lord Tywin's chamber Ser Gregor is tasked with finding the culprit. Tywin fears that he was the intended target and has Ser Gregor hang dozens of their own men. Ser Gregor suggests that an infiltrator from the Brotherhood Without Banners was responsible and Lord Tywin dispatches him to pressure the smallfolk of the Riverlands into giving up the members of the Brotherhood. Tywin marches back to the Westerlands and leaves Gregor to serve as castellan at Harrenhal.

Season 3
Robb Stark and his army get to Harrenhal, finding that Gregor Clegane has left the castle with his men. To their horror, they discover that Ser Gregor has executed the remaining 200 Northmen and Rivermen prisioners at Harrenhal, leaving their bodies to rot.

In the books
In the A Song of Ice and Fire novels, Ser Gregor Clegane is a savage brute of a man, freakishly tall at over 7 feet in height. Known as "the Mountain That Rides", Gregor is one of Tywin Lannister's chief enforcers. Gregor's knighthood is regarded as a hypocritical mockery of justice by many, as he is a thoroughly dishonorable and undisciplined butcher. While Gregor is so strong that he can easily fight the strongest knights in Westeros, his greatest enthusiasm in wartime is for burning out the homes of peasants who cannot possibly fight back, and torturing their women and children to death. Indeed, Gregor's immense size isn't really his main attribute to Tywin, so much as his utter enthusiasm for committing atrocities. As a "might makes right" mentality, Gregor feels that his immense bulk and strength gives him impunity to behave as his does, as few would dare to challenge him. While Gregor is incredibly dangerous in combat, he relies more on sheer strength than on speed or skill. Gregor has gone through multiple wives, who died from the extremely rough treatment they received from Gregor, though there are rumors that he killed them on purpose. His father and younger sister also died suspiciously. Sandor Clegane left when Gregor succeeded their father and never returned.

When Sandor is told by Joffrey to escort Sansa back to the Red Keep after the tournament feast he tells her the story of how his face was burned (not Littlefinger as happens in the TV series). A wood carver gave toys to both of the Clegane children in order to gain their father's patronage. Sandor wanted the articulated jointed knight that Gregor got so he took it. Gregor was ten and already big enough to be training so he didn't even care about the toy, but when he found six year old Sandor playing with it without warning he pushed Sandor's head into a brazier and held him there. It took three men to get Sandor away from him and their father told people that Sandor's bed linens had caught fire. It was later when Gregor was anointed a knight that Sandor Clegane lost all respect for the institution of knighthood and has steadfastly refused to be knighted himself.

Sandor also tells Sansa that the death of Hugh of the Vale was not a tournament accident. Ser Hugh had obviously put on the armor himself and had not set the neck protector correctly. He says Gregor saw that and thus could have sent the blow elsewhere and that the lance didn't just accidentally deflect upward as Gregor puts his lance exactly where he intends it to go every time. He meant to kill Ser Hugh, though it isn't clear if this was an assassination to silence Hugh, or just Gregor enjoying the carnage.