Cersei Lannister is a prominent character from the fantasy series A Song of Ice and Fire by George R.R. Martin, which was adapted into the television show Game of Thrones. She is known for her intelligence, ambition, and ruthless nature, often prioritizing her family's power above all else. Cersei is the daughter of Tywin Lannister and has a twin brother, Jaime Lannister, with whom she shares a complicated relationship. Throughout the series, Cersei seeks to secure her position as the ruling queen of Westeros. Her character is marked by a desire for revenge against those who threaten her family, leading to numerous conflicts with other key characters, including Daenerys Targaryen and Tyrion Lannister. Cersei's journey explores themes of power, loyalty, and the consequences of ambition.