In "Death Note," the main character, Light Yagami, initially believes that sacrificing his morality by using the Death Note to eliminate criminals will lead to a greater good of creating a more just society. However, as the series progresses, Light's actions become increasingly morally questionable as he begins to justify killing innocent people and manipulating others to achieve his goals. This exploration of sacrificing morality for the greater good ultimately leads to a complex examination of ethics, power, and the consequences of one's actions.