Youngest child of Lord Tywin Lannister and Lady Joanna, born at Casterly Rock in 273 AC, his coming killed his mother in childbed and earned him his father's lifelong contempt. Stunted of leg and waddle-gaited, with one eye black and one eye green and a brow too heavy for his face, he was named the Imp before he was weaned and learned early that a dwarf's only armor against the world was wit, wine, and books. At thirteen he came upon a girl set upon by robbers on the roseroad and saved her with his brother Jaime; she was Tysha, a crofter's daughter, and the two were wed by a drunken septon before Tywin learned of it, annulled the union, and had the guards of Casterly Rock take her one after another in Tyrion's sight, paying her a silver for each man and a gold for the last because she was a Lannister's whore. Thereafter he took his pleasure where he could buy it, served as cupbearer and reader to his nephew Prince Joffrey, and rode north with King Robert's progress to Winterfell, where he climbed the Wall in the cold company of Jon Snow and pissed off the edge of the world.
Returning south, he was taken on the kingsroad by Catelyn Stark and brought to the Eyrie for the murder of Bran Stark and the poisoning of Jon Arryn, charges he had no hand in; he won his freedom in a trial by combat fought for him by the sellsword Bronn against Ser Vardis Egen. He gathered the clansmen of the Mountains of the Moon, the Stone Crows and Black Ears and Burned Men, and brought them down to his father's army; Lord Tywin sent him to King's Landing as acting Hand of the King to bridle Cersei and the boy Joffrey. He hoarded wildfire, hammered an iron chain across the mouth of the Blackwater, and burned half of Stannis Baratheon's fleet at the river's mouth, then led a sortie out the Mud Gate where Ser Mandon Moore tried to kill him at his father's bidding and took the better part of his nose with a sword stroke. For his pains he was set aside as Master of Coin upon Lord Tywin's return, married on three days' notice to the thirteen-year-old Sansa Stark to set a Lannister claim upon Winterfell, and seized in the throne room when Joffrey choked to death at his own wedding feast.
He was tried at the Red Keep and condemned on the perjured word of his paramour Shae, demanded trial by combat, and saw Prince Oberyn Martell of Dorne stand his champion and die beneath the gauntlet of Ser Gregor Clegane. On the eve of his execution Jaime came to free him by a passage of Varys, and confessed that Tysha had been no whore, that Tywin's tale had been a lie and the marriage true, whereupon Tyrion lied in turn about Joffrey and went looking for his father. He found Shae naked in Lord Tywin's bed, strangled her with the chain of golden hands she wore at her throat, and put a crossbow bolt through his father's bowels as he sat the privy. Smuggled across the narrow sea in a barrel by Varys, he came to Pentos and the manse of the cheesemonger Illyrio Mopatis, who set him on the road to Daenerys Targaryen with talk of dragons; on the Rhoyne he fell in with the exiled knight Jorah Mormont, was taken by slavers, sold in the fighting pits of Meereen, and at last found service among the sellswords of the Second Sons before the walls of the dragon queen's city.