Light Yagami's need for control over life and death is primarily driven by his strong sense of justice and desire to create a utopia where he can eliminate all criminals and bring about peace and order to the world. This desire is fueled by his belief that he alone has the intellect and moral superiority to wield the power of the Death Note to pass judgment on those he deems unworthy of life. Additionally, Light's ego and thirst for power play a significant role in his pursuit of control over life and death, as he becomes intoxicated with the idea of being a god-like figure who can shape the world according to his own vision.
