Light Yagami's need for validation and recognition is primarily driven by his inflated sense of self-importance and desire for power. Throughout the series "Death Note," Light is depicted as a highly intelligent and ambitious individual who believes that he alone possesses the capability to bring about justice and create a perfect world. His need for validation stems from his belief that he is superior to others and that his actions are justified in the pursuit of his vision of a utopian society where he is revered as a god-like figure. Additionally, Light's desire for recognition feeds into his ego and fuels his relentless pursuit of acclaim and adoration from others, further solidifying his perception of himself as a superior being.