Ser Jaime Lannister was the eldest son of Lord Tywin Lannister, younger twin brother of Queen Cersei Lannister, and older brother of Tyrion Lannister. Jaime previously served in the Kingsguard of Aerys Targaryen, known as the Mad King, before infamously murdering him during the Sack of King's Landing, earning Jaime the sobriquet of the "Kingslayer".