What does Cassia symbolize in the book?

Cassia serves as a symbol if individuality. She begins the story as a comfortable, happy pawn in the Society’s totalitarian game. As she slowly becomes both self-aware and aware of the Society’s fallibility, she begins to question the status quo. Over the course of the book, she becomes completely disillusioned to the Society's lies; ultimately, she is willing to betray her Match with Xander for the chance at liberation and happiness with Ky.