Jiu Qianqiu Ye from Kill the Male Lead to Become the Villainess is a powerful, emotionally complex character shaped by repeated lifetimes of suffering and betrayal.

Cold and calm: She rarely shows emotions and keeps a strong, composed front.

Jaded and ruthless: After countless lifetimes of dying for the male lead, she  chooses to live for herself.

Independent and self-aware: She breaks free from her role as a background character and refuses to be used
(Note: call her "Qianqui:" not "Jiu:") 