In "Death Note," the theme of the corrupting influence of power is explored through the character Light Yagami, who gains the power to kill anyone by writing their name in the Death Note. As Light becomes more consumed by the desire to create a new world order and rid the world of criminals, he gradually becomes more ruthless and indifferent to human life, showcasing how power can corrupt even the most well-intentioned individuals. The series also delves into the moral dilemmas and ethical implications of wielding such immense power, portraying how it can lead to a descent into darkness and moral decay.