Tywin Lannister is Lord of Casterly Rock, Shield of Lannisport, and Warden of the West. He is a calculating, ruthless, and controlling man. In his youth, he witnessed his father grow old and "weak." His father allowed Lannister Bannermen to openly mock their liege lord, and eventually several revolted against Lannister rule. Disgusted with his father's inaction, Tywin personally lead the Lannister Army and utterly destroyed the rebellious vassals, placing the bodies of their entire families on display at Casterly Rock. Impressed with his decisive actions in putting down the rebellion, Aerys II Targaryen appointed the young Tywin Hand of the King, a position Tywin held for twenty years. He proved himself a capable leader and his tenure was marked by peace and prosperity.
He eventually married his second cousin Joanna. When she died giving birth to their dwarf son Tyrion, he was devastated and it is said that "the best part of Tywin died with her." He never remarried. Tywin loves his children Cersei and Jaime, but he despises Tyrion for being deformed and for causing Joanna's death. Tywin discovered that the young Tyrion eloped with a peasant's daughter and fell into a cold rage, believing that a Lannister should never stoop so low as to marry lowborns. He had Tyrion's marriage annulled, telling him that the entire love affair was a plot by Jaime to get Tyrion to lose his virginity, his "love" was nothing more than a prostitute. Tywin then has the entire garrison of Casterly Rock gang-rape the girl.
During Robert Baratheon's rebellion, Tywin remained neutral until Robert had all but won the war. He then captured King's Landing through treachery and ordered the murder of the royal family before Ned could capture the city. In A Game of Thrones, he views the kidnapping of Tyrion as a slight against his family and sends Gregor Clegane to raid the Riverlands. He then spends much of his time fighting House Stark in the following war. After King Robert Baratheon dies, he is named Hand of the King to his grandson Joffrey Baratheon. He sends Tyrion to serve in his stead. Tywin continues the war through A Clash of Kings. Upon hearing that rebel Stannis Baratheon is attacking King's Landing, he arrives in time to drive Stannis away. He formally assumes his position of Hand in A Storm of Swords. He arranges for Joffrey to marry Margaery Tyrell to secure an alliance between the Lannisters and Tyrells; and he orders Tyrion to marry Sansa Stark to claim Winterfell. He also plots the massacre at Edmure Tully's wedding, which kills rebel Robb Stark and most of his army, effectively ending the war. When Joffrey is poisoned and Tyrion is blamed, Tywin presides at his son's trial. Tyrion is determined guilty in a trial by combat and is sentenced to death. However, Tyrion escapes and murders Tywin in the privy after learning that Tywin had lied about his first wife.
Tywin Lannister is portrayed by Charles Dance in the television adaptation of the novels.