Polliver is a minor antagonist in A Song of Ice and Fire. He is a is a man-at-arms in service of House Clegane. He serves under Ser Gregor Clegane, as part of the men who are mostly referred as "the Mountain's Men".
He is a grim and methodical fighter,but Arya Stark does not believe him to be as evil as his more violent comrades.
In the TV series Game of Thrones, Polliver is not a Mountain's man, but a man-at-arms in service of House Lannister. He serves under Ser Amory Lorch. During the ambush at the Gods Eye, Polliver takes Arya Stark's sword, Needle, and says he will pick his teeth with it. He then approaches Lommy Greenhands, who has been shot with an arrow during the fight and claims that he might need to be carried. Polliver initially lifts him up, but as he does, skewers Lommy through the neck with Needle.
At Harrenhal, Polliver beats an old woman prisoner for asking him for a crust of bread. Gendry is selected to be tortured while Polliver stands guard. 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. Polliver 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. Polliver catches Arya looking at Needle in his sword belt and orders her to kneel, calling her boy. Tywin immediately realizes that she is a girl and calls Polliver an idiot. He asks why she has dressed as a boy and she says that it was safer to travel. He says that she is smart and orders the prisoners be put to work. He says that Arya will be his new cupbearer.
Polliver doesn't make another appearance until Season 4, when Arya and Sandor Clegane encounter him at a tavern with some other kingsmen, where they are preparing to rape the innkeeper's daughter. Polliver recognizes Sandor, asks the innkeeper to give him an ale, and offers to have him join him and his cohorts in raping, pillaging, and plundering. The Hound refuses, saying, "Fuck the King". Insulted, Polliver insults the Hound for abandoning King's Landing at the Battle of Blackwater Bay. The Hound counters by demanding that they give him a chicken.
Polliver asks the Hound if he has money to pay for a chicken, to which the Hound replies that Polliver and his men didn't pay for theirs; Polliver counters by saying that he is a kingsman, so he has the right to do that. He once again demands a chicken; Polliver tells him he'll give him one if he gives Arya to one of his men to be raped. The Hound then steals Polliver's drink and downs it, then demands two chickens. Polliver is confused as to why he wants the chickens so badly, but the Hound rebukes him, saying he'll eat every chicken in the room if Polliver doesn't shut up. Polliver figures out that this is a euphemism that he kill all of them because of their disgusting actions, and tells the Hound that he lives to serve the king, and he asks him if he was willing to die for a few chickens. Chaos then erupts as Polliver and his men fight the Hound and Arya.
Towards the end of the skirmish, Arya takes back Needle and slashes Polliver's hamstring. She stands over him as he lays on his back and recreates Lommy's death scene, taunting him with the same words Polliver had used prior to killing Lommy: "something wrong with your leg boy? Can you walk? I've got to carry you?" She then repeats what he said to her when he stole Needle, "fine little blade; maybe I'll pick my teeth with it." A look of recognition comes over Polliver's face as he finally remembers her and what she is referring to. She slowly sheaths Needle into his neck, completing Lommy's death scene down to the gurgling of arterial blood from Polliver's mouth. As she watches him choke on his own blood, a look of deep fascination and satisfaction resides on her face.