How has Jack's personality developed during his stay on the island?

Jack Merridew is the leader of the choir boys who were on board the plane. When the boys all come together for the first time, it is suggested that a leader be chosen. Ralph and Jack are the two candidates, and Jack is clearly disappointed when he is not chosen. However, Jack jumps at the opportunity to lead his choir as a group of hunters. Jack is also quick to volunteer to keep the signal fire going. Jack seems very helpful at the beginning.

As talk of the beast continues in the group, Jack becomes annoyed and continuously brushes off the idea of danger on the island. This suggests to the reader that Jack is fearful of the island and has chosen to hide this fear in his hunting abilities and his growing savagery. When Ralph later insults the hunters after Jack and some of the others run from the beast on the mountainside, Jack leaves Ralph’s group and takes most of the older boys with him.

Jack has embraced the savagery of the island and has decided that all they should be required to do is hunt all day. Jack tells his tribe that he wants to have fun all day, but at the same time he punishes a boy in his tribe for reasons he does not share with the others. This suggests that Jack has chosen to beat this boy simply because he wants to.

Jack has developed a dislike for Ralph that is based partially on his jealousy that Ralph is the leader and partly on Ralph’s friendship with Piggy. Jack wants to hurt Ralph. So, he first steals all of his group members, and he kills Piggy later in the story. Jack then decides to hunt Ralph, taking his brutality to its final and most horrifying level. Luckily for Ralph, the boys are rescued, ironically because Jack has ordered a fire in the jungle to flush out Ralph.