The emergence of evil in the character of Jack Merridew is central to Golding's theme in Lord of the Flies of the intrinsic nature of evil in man. Suggestions of the intrinsic evil in human nature are made first through the character of Roger, who in Chapter Four sadistically wishes to throw stones at little Henry who plays with the small crabs on the shore:
Roger stooped, picked up a stone, aimed, threw it at Henry--threw it to miss. The stone, that token of preposterous time, bounced five yeards to Henry's right and fell in the water. Roger gathered a handful of stones and threw them....Here, invisible yet strong, was the taboo of the old life. Round the squatting child was the protection of parents and school and policemen and the law. Roger's arm was conditioned by a civilization that knew nothing of him and was in ruins.
Once the conditioning of society is removed as it is on the island, the sadistic Roger and Jack, who is "a continent of experience and feeling" apart from Ralph, begin their descent into savagery as the evil nature intrinsic in them is free to emerge. Having become the chief of the hunters, Jack engages in primordial activities such as killing a pig and stealing the fire. With such savage actions, along with his masking of his features, the primal urges of violence and jealousy are given free rein in Jack and his inherent evil emerges as his power over the others increases.