The Cleganes hold a keep as sworn knights. The first Clegane was raised to knighthood after saving Lord Tytos Lannister from a mountain lioness at the cost of a leg and three hunting hounds. His grandson Ser Gregor, a huge and fierce knight called the Mountain that Rides, now rules the keep. He was a knight of 17 years when he took part in the Sack of King’s Landing, where it’s said that he killed Prince Aegon and raped Princess Elia before putting her to the sword.
Ser Gregor’s father died in a hunting accident and the death of his sister was under strange circumstances. On his father’s death, Gregor’s young brother Sandor Clegane left their lands never to return, swearing his sword to the Lannisters and becoming sworn shield to Prince Joffrey. Ser Gregor has no children, although he has had two wives and is preparing to marry a third.
Sandor Clegane, known as the Hound, was made a member of the Kingsguard after the dismissal of Ser Barristan Selmy from his post, although the Hound refused to swear a knight’s oaths. Since then, he has fled King’s Landing after showing his fear and refusing to charge into the fire-swept battle as the Hand, Tyrion Lannister, demanded. He turned up in the riverlands, where he was robbed by the brotherhood without banners, won a trial by combat against Lord Beric Dondarrion, and captured Arya Stark. He was left seen weak and feverish from an infected wound.
Ser Gregor was used by Lord Tywin to raid into the Riverlands and go about destroying castles and holdfasts. He lead the van at the Green Fork and briefly won the crossing of the Red Fork at Stone Mill before being thrown back by Ser Edmure Tully and his reserve. He was apparently too wounded to fight at the battle at the Blackwater, but was able to be the crown’s champion in the trial by combat against Tyrion Lannister’s champion, Prince Oberyn. Ser Gregor was wounded and poisoned by the Red Viper, but killed the Dornish prince while admitting aloud that he had in fact raped Elia of Dorne and killed her and her children. He is apparently on his deathbed.