Jaime Lannister

Ser Jaime Lannister is a major character in Game of Thrones. He is played by Nikolaj Coster-Waldau and appears in the first episode of the series.

Jaime is the eldest son of Lord Tywin Lannister, the twin brother of Cersei Lannister and the elder brother of Tyrion Lannister. He is an extremely skilled warrior, held to be one of the greatest warriors in all of Westeros. He is a member of the Kingsguard, the King's elite bodyguard which consists of the seven greatest knights on the continent. He is noted for his arrogance.

In the books
In the Song of Ice and Fire novels, Jaime Lannister was a prodigy of a warrior. Knighted at fifteen and appointed to the Kingsguard by King Aerys II Targaryen soon after, he served alongside such great warriors as Ser Arthur Dayne, the infamous Sword of the Morning, and Lord Commander Gerold Hightower. However, Jaime's appointment angered his father, Tywin, since it meant Jaime was no longer his heir, the honour of which instead fell to Tywin's misshapen and hated youngest son, Tyrion. At the climax of Robert's Rebellion, when the Lannister armies stormed King's Landing, Jaime betrayed his king by murdering him at the foot of the Iron Throne itself.

Jaime was forgiven his crime by King Robert Baratheon and reinstated to the Kingsguard, but he has carried the name 'Kingslayer' ever since.