Cersei Lannister— sorry, Queen Cersei of the House Lannister, the First of Her Name, Queen of the Andals and the First Men, Protector of the Seven Kingdoms — is perhaps most deliciously complex character on Game of Thrones. She's a cruel femme fatale, a savagely protective mother, and a power-hungry tyrant who has zero insight into her incompetence.
When we left season 6, Cersei had come out on top as she ascended to the Iron Throne after murdering the Tyrells in cold blood. That scene of her smugly sipping her wine while she surveys the destruction of the Sept of Baelor is absolutely iconic.
But for those of us who read the book series that the show is based on, A Song of Ice And Fire, it was surprising that Cersei became such a force to be reckoned with. Her character was always in a position of power, and she always made ill-advised decision to secure herself larger pieces of the pie, but plot lines didn't revolve around her as much as in the show. Cersei didn't even have her own point-of-views chapters in the books until A Feast for Crows, which is the fourth book in the series. She's got a much larger footprint in the TV show than in the books. Indeed, i09 talks about a statistics company who put this disparity into numbers: she gets over 200 minutes of screen time in 52 episodes, compared to only 12 chapters in the book series (out of 344 total chapters in 6 books). The upgrade is in how prominently Cersei is featured in the television show over the books, and the difference is noticeable.
As a character, Cersei is in the instigator of so many evil plot lines in the show, and is performed masterfully by Lena Headey. We just can't take our eyes off her when she saunters on screen. Every time she's plotting something malevolent in the Red Keep, she's stealing the scene. Now that she's claimed the ultimate power in Westeros, it's safe to say her role is only going to grow — or she's in serious trouble. There's no middle ground with her character. As Cersei cooly said in season 1, "in the game of thrones, you win or you die."