The title is important because as the story progresses, the boys succumb to their inner beast and allow it to rule their thoughts and actions. In chapter 8, Simon sees the pigs head that Jack has left on a stake. This becomes the "Lord of the Flies," and it speaks to Simon, foreshadowing the sadistically evil events that are to occur. The "Lord of the Flies" is a demonic character that reveals that everyone is susceptible to the evil within. Although the "Lord of the Flies" is only mentioned this once, it is extremely significant because it refers to the inherent evil that all are prone to unleash, and it is one of the major themes of the novel.
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