Light Yagami, the main character in the manga and anime series "Death Note," initially believes that his actions as Kira are justified in his quest to rid the world of criminals and create a utopia. He rationalizes his actions by convincing himself that he is doing good by eliminating wrongdoers. However, as the series progresses, Light's god complex and desire for power become more pronounced, leading him to make increasingly morally questionable decisions. Ultimately, Light becomes consumed by his own sense of righteousness and loses touch with his original intentions, showcasing the complex and morally ambiguous nature of his character.