Eldest daughter of Lord Tywin Lannister of Casterly Rock, Cersei is twin to Ser Jaime Lannister, the Kingslayer. Blonde, green-eyed, and one of the most beautiful women in the Seven Kingdoms, she has the Lannister pride and the ferocity of the mother lion when her children by King Robert are endangered. Her marriage to the king is loveless—a political marriage only, to secure her father’s allegiance after Robert won the Iron Throne—and their conflicts can be brutal. Her brother Jaime is often by her side, serving as her sworn shield as one of the knights of the Kingsguard. Her other brother Tyrion, however, is an affront to her sensibilities, and she denigrates the Imp mercilessly.
Cersei travels to Winterfell with her husband Robert, and it is clear there are serious tensions between them. When Bran Stark witnesses her engaged in sex with her brother Jaime, she witnesses Jaime’s throwing of the child down from the tower. However, Bran survives, and she later meets with Catelyn and speaks of her firstborn child who died in the cradle. Departing Winterfell, she plays an instrumental role in insuring that Sansa’s wolf, Lady, is killed as punishment for Arya and Nymeria harming Prince Joffrey. In King’s Landing, the queen clearly plots against Ned Stark and the king, but with Robert she shares a moment in which she reveals that she had loved him once. When it is clear Ned Stark has discovered the truth of her relationship with Jaime—a fact she admits to when he confronts her—and is preparing to tell Robert, she has her cousin Lancel give Robert too much strong wine, leading to his untimely death. While Lord Stark prepares to reveal the truth and set Stannis on the throne, with the help of Littlefinger the queen undermines his plans and makes him a prisoner. However, he is later executed by Joffrey without her consent, which causes further trouble.