House Clegane is sworn to House Lannister. The first Ser Clegane was kennelmaster at Casterly Rock until he saved Lord Tytos Lannister from a lion and lost a leg in the effort. As a reward, Lord Tytos gave him lands and a towerhouse and took his son as his squire. Their sigil is three dogs on a yellow field; the three dogs represent the dogs that saved Lord Tytos.
Ser Gregor Clegane, head of House Clegane and Sandor Clegane’s older brother, is a retainer to House Lannister. Gregor is a freakishly large man, over seven and a half feet tall, and possesses enormous strength. For this he is often called “The Mountain That Rides” or simply “The Mountain”. He is well known for his size, cruelty, and prowess in battle.
Gregor’s history is dark and filled with blood. He caused Sandor’s facial scars at a young age when he held his six year old brother’s face to a hot brazier as punishment for taking a discarded toy of his. There were rumors that Gregor killed his father, sisters, and his first two wives. He had committed numerous rapes and murders, but his most infamous deed came from his service to House Lannister during Robert’s Rebellion. He was one of the first Lannister soldiers to enter King’s Landing during its sack at the end of Robert Baratheon’s rebellion. He killed the infant Aegon, son of Crown Prince Rhaegar Targaryen and his wife Elia of Dorne, by dashing the boy’s head against a wall, and then raped and murdered Elia, supposedly with the boy’s blood and brains still on his hands.
During the War of the Five Kings, Ser Gregor led raiding parties in the Riverlands as a bannerman for Tywin Lannister. His band caused enormous destruction, burning, raping, torturing, and killing entire villages with impunity. For a time he unknowingly held Arya Stark as a captive, and she witnessed many of his atrocities first hand.
When Tyrion Lannister demanded trial by combat to prove his innocence in the murder of Joffrey Baratheon, Gregor championed Tyrion’s accuser, Queen Cersei. Elia’s brother Oberyn Martell, seeing a chance to fulfill his family’s long-held wish of vengeance against her defilers, championed Tyrion in opposition. Gregor fought with heavy armor and wielded a greatsword in one hand, but Oberyn outfought him with speed and a poisoned spear. After being poisoned and crippled with numerous wounds, Gregor managed to grab hold of Oberyn and pulverize his skull with a punch from his mailed fist. Despite Gregor’s victory, Oberyn’s poison resulted in a long, agonizing death by mortification. Insensible and dying, he was brought to the medical experiment dungeons below King’s Landing by Qyburn and has not been seen since. Qyburn told Cersei that the poison was Manticore venom which had been thickened with sorcery so that it would stretch out his agony instead of killing instantly. An enormous skull said to be Gregor’s was sent to Dorne as recompense for the deaths of Elia, Aegon, and Oberyn. However, mentions of Qyburn’s unbeatable champion for Cersei and order of a breastplate too large for any man have left suspicions on whether Westeros has seen the last of Gregor Clegane.
Sandor Clegane is the younger brother of Gregor Clegane and a retainer to House Lannister. He is nicknamed “The Hound,” in part because his family arms feature three dogs, and in part for his savage nature and unquestioning obedience to his masters. He regularly wears a distinctive helm in the shape of a snarling dog’s head. He is considered one of the most dangerous fighters in Westeros, though he frequently drinks himself into stupors. As a child, Sandor received gruesome facial burns when Gregor shoved his face into a brazier. He now has a phobia of fire, and loathes his brother, Gregor Clegane, and the hypocrisy of knighthood in general.
Sandor acted for a time as bodyguard and servant of Joffrey Baratheon, who regularly called him “Dog”. He won the Hand’s Tourney after saving Loras Tyrell from Gregor’s wrath. While drunk off his winnings, Sandor became enamored with Sansa Stark, but also mocked her for her polished manners, calling her a “little bird” who chirps on command. Sandor was eventually named to the Kingsguard, despite refusing to become a knight, and in this capacity he was often assigned to watch over Sansa. Despite his loyalty to Joffrey, he strategically defended her from Joffrey’s wrath several times, and was the only member of the Kingsguard who was never commanded to beat her. He fought heroically during the Battle of the Blackwater, but eventually deserted after refusing to return to the flame-choked battlefield. Before fleeing, he found Sansa Stark. He offered to take her with him, but instead settled on a song.
As a vagabond, he was arrested by the Brotherhood without Banners, which also had Arya Stark in its custody. The Brotherhood put Sandor on trial for Lannister atrocities – Arya in particular hated Sandor because he once killed a friend of hers. He chose trial by combat, facing the Brotherhood’s leader Beric Dondarrion. Beric fought with a flaming blade, but Sandor managed to defeat him despite his fear of fire. The Brotherhood stripped him of almost all his possessions, but set him free. Sandor returned to the Brotherhood to get his tourney winnings back, but kidnapped Arya instead, with the intention of ransoming her off to one of her relatives. He took her to meet her brother Robb Stark at the Twins, but arrived during the Red Wedding massacre. Sandor stole Arya off again in the hopes of ransoming her off to another family member. At a roadside inn, they ran afoul of three of Gregor’s men and Sandor was seriously injured in the ensuing fight. After his wounds became infected he was no longer able to confine Arya. Still hating him for killing her friend, Arya abandoned him, refusing even to grant him the mercy of a quick death.
Sandor’s fate becomes uncertain after this point. The head of a nearby monastery claimed to have buried the “Hound” after encountering him dying in the woods. He also stabled Sandor’s warhorse, Stranger, at the monastery. However, there are hints in the passages that suggest that Sandor may still be alive, and has joined the monastery. Meanwhile, a deserter from the Brave Companions, Rorge, recovered Sandor’s helm from his gravesite and assumed his identity during a brutal spree of banditry. Rorge was later killed by Brienne of Tarth and the helm was then taken by Lem Lemoncloak, a member of the Brotherhood without Banners.