Light Yagami's actions in the series "Death Note" have a significant impact on the portrayal of justice and morality. His belief in his own twisted sense of justice, where he sees himself as a god-like figure who can rid the world of criminals, challenges traditional notions of morality and justice. This leads to complex discussions within the series about the ethics of his actions, the consequences of playing judge, jury, and executioner, and the blurred lines between good and evil. The character of Light Yagami serves as a catalyst for exploring these themes and raises thought-provoking questions about the nature of justice and morality.