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  ===House Lannister===
  * '''Gregor Clegane''' (seasons 1–2, 4–8) portrayed by Conan Stevens in season 1, by Ian Whyte in season 2, and by Hafþór Júlíus Björnsson from season 4 onwards.Hafþór Júlíus Björnsson, the third and latest actor to portray Ser Gregor Clegane Ser Gregor Clegane is a huge knight and the elder brother of Sandor Clegane. Called "the Mountain That Rides", he is known for his incredibly cruel nature and uncontrollable temper. His size and strength make him a fearsome warrior, and he has earned a reputation for cruelty and brutality. He is able to wield a two-handed sword one handed. When they were children, Gregor shoved Sandor's face into a brazier, gruesomely scarring him. In Season 1, Tywin Lannister sends him to raid the Riverlands. Beric Dondarrion is sent to arrest Gregor. When war breaks out, Gregor is given command of Tywin's vanguard and left flank and leads his men through intimidation. In Season 2 he is left to command Harrenhal in Tywin's absence and to find and destroy "the Brotherhood Without Banners", invoking the escape of Arya, Gendry and Hot Pie from Harrenhal. He later abandons the castle after slaughtering the prisoners and is defeated by Edmure Tully at the Stone Mill, but manages to escape back to the Westerlands. Robb chides his uncle, having planned to draw the Mountain into a trap of his own making to be captured or killed. In season 4, Gregor is chosen as Cersei's champion for Tyrion's trial by combat, and fights Oberyn Martell, Tyrion's champion who wants to kill Clegane as revenge for the needless murder of his sister, Elia Martell Targaryen. Oberyn sustains several serious injuries to Clegane with a weapon that is laced with poison, but Clegane kills Oberyn by crushing his skull, while admitting that he did rape Elia, killed her children and enjoyed it, before collapsing from his own injuries. It is later revealed that Clegane has been poisoned with manticore venom, a poison that Oberyn had laced his weapon with, and that he is slowly dying. Cersei enlists ex-maester Qyburn to save him, though Qyburn claims that the procedure will "change" Clegane. The procedure is a seemingly a success, as Gregor has become active again and joins the Kingsguard as a personal knight for Cersei, though the procedure has changed his physical appearance and his behavior. In the sixth season, he continues to act as Cersei's bodyguard to intimidate all those who may bother or mock her. After Cersei destroys the Great Sept of Baelor and retakes power, she has Gregor torture Septa Unella in revenge for Unella torturing her during her time in prison.
  * '''Kevan Lannister''' (seasons 1–2, 5–6) portrayed by Ian Gelder. Lord Tywin's younger brother, Captain of his Guard, Ser Kevan Lannister is a skilled warrior but overshadowed by his brother Tywin to whom he is deeply loyal and obedient. Unlike his older brother, Kevan is very amiable and cares more about the safety of his family members even if it will humiliate the family's honour. In Season 1, he is present when Tyrion returns from the Vale and informs him on Jaime's military victories against Tully bannermen. After Jaime's capture, he suggests to his brother that they "should sue for peace" which is immediately refuted by Tyrion who reminds that Ned Stark's beheading prevents it. In Season 2, he sits on a war council in Harrenhal, surmising (correctly) that Robb Stark would not march on Casterly Rock until "at full force" and also suggests that Cersei and her children leave King's Landing before Stannis Baratheon sacks the city but the proposition is countered by Tywin, refusing to surrender the Iron Throne. In season 5, he returns to King's Landing to attend Tywin's funeral alongside his only surviving son, Lancel, who has joined the Sparrows movement, which Kevan disapproves. He later refuses to serve on Cersei's Small Council, in spite her offering him the position of "Master of War", questioning her authority, and returning to Casterly Rock until the King himself calls for him. When his niece is arrested by the Faith Militant for sleeping with his son among other sins, Grand Maester Pycelle summons him back to offer him the position of Hand of the King. He later is present at Cersei's return to the Red Keep, immediately after her enduring Walk of Atonement. In the sixth season, Kevan continues to serve as Tommen's Hand while attempting to deal with the High Sparrow without bloodshed and spurning Cersei's attempts to regain influence in the royal court. On the day of Cersei's trial, Kevan is killed when Cersei has the Great Sept of Baelor destroyed with wildfire.
  * '''Lancel Lannister''' (seasons 1–2, 5–6) portrayed by Eugene Simon. Eugene Simon Lancel Lannister is the eldest son of Kevan Lannister and cousin of Cersei, Jaime, and Tyrion Lannister. He served as King Robert's squire; in which he is clumsy and incompetent in his duties leading Robert to dislike him intensely. In Season 2, Cersei knights him for his part in Robert's death. When Jaime goes to war, Cersei takes Lancel as a lover because he resembles her brother. Tyrion eventually discovers the affair and blackmails Lancel into spying for him. During an attack on King's Landing, Lancel guards Cersei's son King Joffrey Baratheon and takes a serious wound in the fighting, causing him to retreat. When Joffrey later abandons the battle out of cowardice, Lancel pleads with Cersei to let him take Joffrey back to the battle in order to inspire the troops, but Cersei, clearly more concerned for Joffrey than the city, refuses to listen. In season 5, he and his father return to King's Landing to attend Tywin's funeral. Lancel joins the sparrows, a devout religious movement, and apologises to Cersei for the sins they committed together, such as their affair and conspiracy to murder Robert Baratheon. With the re-establishment of the Faith Militant, Lancel abandons his family name and leads the sparrows on a rampage throughout King's Landing, arresting Ser Loras Tyrell in the process. Later, on Littlefinger and Olenna Tyrell's urging, he confesses his own sins to the High Sparrow, which leads to Cersei's arrest. In the sixth season, Lancel continues to serve in the Faith Militant. On the day of Cersei and Loras's trial, he is lured by one of Qyburn's little birds to the catacombs underneath the Great Sept of Baelor, where he is stabbed in the spine, rendering him unable to use his legs. He spots a cache of wildfire rigged to explode and crawls towards it, but is too late to stop the detonation and is the first to die.
  * '''Polliver''' (seasons 2, 4) portrayed by Andy Kellegher. A Lannister man-at-arms who comes into possession of Arya Stark's sword; Needle. He captures Arya – believing her to be a recruit of the Night's Watch called "Arry" and takes her sword which he then uses to kill a crippled Lommy after he asks Polliver to carry him. In Season 4, he inadvertently crosses paths with Arya and Sandor Clegane in an inn in the north. After a brief exchange of insults, a fight breaks out and Polliver's comrades are slain by Clegane. Arya wounds Polliver from behind, retrieves Needle and kills him in exactly the same manner that he killed Lommy.
  * '''Alton Lannister''' (season 2) portrayed by Karl Davies. A cousin of Cersei, Jaime and Tyrion Lannister, and a captive of Robb Stark. In the books there is no character by this name. Here the character Cleos Frey, also a cousin to the Lannisters, has the role of being a captive of House Stark and delivering terms to House Lannister. While held prisoner in the same cell he talks with his cousin Jaime at Stark's camp, he talks about the time he was allowed to prove himself by squiring for Jaime in a tourney, however during this encounter he is killed by Jaime in an attempt to escape.
  * '''Amory Lorch''' (season 2) portrayed by Fintan McKeown. Ser Amory Lorch is a knight and loyal but brutal bannerman of House Lannister. He catches Arya in stealing a parchment containing war orders concerning her brother Robb Stark. She manages to escape him, then finds and hurries the assassin Jaqen H'ghar, to kill Ser Amory to repay the second of the three "lives" he owes her. Before Ser Amory can denounce Arya, he drops dead on the doorstep of Tywin's chambers with a poisoned dart lodged in his neck, as Tywin (who comes to believe the attempt was on his life) raises the alarm. The Mountain subsequently kills a number of Lannister soldiers in his hunt for the culprit, but Jaqen leaves Harrenhal without being captured.
  * '''Lord Leo Lefford''' (season 2) portrayed by Vinnie McCabe. Lord Lefford is a powerful Bannerman to Lord Tywin, who fought for him against House Stark. He is Head of House Lefford and Lord of The Golden Tooth.