In Lord of the Flies, it soon becomes obvious that Jack and Ralph have very different characteristics and impressions about leadership. Ralph emulates his father, a Commander in the Navy, believing in the necessity for rules and organization. Jack, on the other hand, as "head chorister" does not believe he needs to earn the respect of the others; he thinks he deserves it because of his presumed status. The boys though are impressed by Ralph and the power of the "trumpet-thing," the conch.
Ralph recognizes Jack's "blush of mortification" and suggests he can lead the choir and they can be whatever Jack wants them to be - hunters, the army, etc. As the story proceeds, Ralph's leadership becomes less effectual as Jack undermines him and Ralph becomes less assertive, showing his weakness which Jack then takes advantage of. Ralph has a belief that good will always win over evil and so does not necessarily recognize the power behind Jack.
Piggy is afraid of Jack and again Jack works on the weaknesses of others and uses these to his advantage. Piggy desperately wants to create an environment similar to the one from which he came and is always wondering what "the grown ups" would do. Without Ralph's full support Piggy cannot stand up to Jack and, although Ralph appreciates Piggy's help towards making him a good leader, he also mocks Piggy's efforts sometimes.
Both Piggy and Ralph are lured by the thought of eating meat from the animals Jack has hunted without even realizing that they are contributing to Jack's all-consuming vision of leadership. Left unchecked, power and control for Jack translate into savagery which the other boys unwittingly support by their actions. It is significant that, when piggy dies, the conch is smashed.
Roger sees Jack as the perfect leader. He is sadistic and supports Jack's mean streak by not only hunting for the purposes of food but for the pure pleasure of killing. He tortures the pig and gives Jack the false impression that there is enjoyment in this, to the point that Jack is so overcome that Simon dies during the frenzy. Jack needs little encouragement to intensify his animal instincts and he is spurred on by the actions or inaction of others, especially Ralph, Piggy and Roger.