Light Yagami's actions, particularly his use of the Death Note to pursue his ideals of creating a perfect world, greatly impact his sense of identity and purpose throughout the series "Death Note." At the beginning, he believes himself to be a justice-driven savior known as Kira, dedicated to ridding the world of criminals. However, as he continues to use the Death Note and becomes increasingly consumed by power, his sense of identity becomes more entwined with his alter ego, leading him to question his original intentions and ethical boundaries. This internal conflict ultimately shapes his sense of self and purpose, driving him further down a dark path of moral ambiguity and self-delusion.