Jaime Lannister is a major character in the first, second, third, fourth and fifth seasons. He is played by starring cast member Nikolaj Coster-Waldau and debuts in the series premiere. Ser Jaime Lannister is a knight of the Kingsguard, the son of Tywin Lannister, twin brother of Queen Cersei Lannister, and older brother of Tyrion Lannister. Previously he served in the Kingsguard of Aerys II Targaryen and, infamously, he betrayed and killed Aerys during the Sack of King's Landing, earning him the sobriquet "The Kingslayer". Jaime is involved in an incestuous sexual relationship with Cersei, and, unknown to most, is the biological father of her three children, Joffrey, Myrcella and Tommen. Jaime visits Winterfell in King Robert's entourage; he pushes Bran Stark from a window when Bran sees him having intercourse with Cersei. Bran survives but is paralyzed from the waist down and has no memory of the event. Evidence implicating House Lannister emerges and sparks a war with the Starks, which eventually escalates into a major conflict. Jaime leaves his post to join his father's attack on the Riverlands. After Joffrey assumes the Iron Throne, Jaime is promoted in absentia to Lord Commander of the Kingsguard. However, his army is routed by Robb Stark's forces during the Battle of the Whispering Wood and he is taken prisoner. Catelyn Stark later releases him with the promise that he will return her daughters Sansa and Arya to her. Escorted by Brienne of Tarth, they begin an arduous journey back to King's Landing, during which Jaime's sword hand is cut off by Locke. Jaime and Brienne eventually reach the capital, where Jaime ultimately helps Tyrion escape from prison for a murder he did not commit, though it indirectly leads to Tywin's murder at Tyrion's hands, which Jaime holds himself partly responsible for.