Lord of the Flies highlights the potential for tragedy when young boys are left to fend for themselves without any "grown-ups" to advise them and to maintain order. Jack and his "hunters" are prime examples of unchecked instincts.
Ironically, Jack is the "chapter chorister" of a group of boys when they find themselves on a deserted island with nothing more than a conch shell to help them keep order. Jack, even at the beginning, thinks that, as choir head and head boy, he would make the best leader, and is surprised and embarrassed when he is not chosen. He is appeased when Ralph suggests that he heads up "the hunters," and, when Ralph, Simon and Jack go to inspect the island, Jack thinks of them as explorers. There is an unspoken bond between them, not the viciousness and cruelty that will ultimately destroy all innocence and fairness.
However, it does not take long for Jack's sadistic nature to reveal itself. Having missed a chance to kill a piglet because of "the enormity of the knife descending and cutting into living flesh..." (Ch 1), Jack vows that, "Next time there would be no mercy."
Even when he is not challenged, Jack thinks that he has to prove himself. When the littleun talks of "the beastie," Jack is quick to show his fearlessness and when Ralph talks of making a fire, instead of respecting Ralph's position, Jack is caught up in the excitement of the fire and the boys instinctively follow him to collect wood. At this stage, there is no maliciousness in Jack's actions, as he and Ralph, "grinned at each other sharing this burden."(Ch 2)
Jack's methods, though, confirm Piggy's initial dislike and distrust of Jack, as Jack "snatched the glasses off his face,"rather than asking him and Jack's contempt for Piggy also begins to reveal itself, a definite indicator of his increasing need to control, even in the presence of the conch as he says to Piggy, "The conch doesn't count on top of the mountain....so you shut up." His initial co-operative spirit is diminishing as he "turned fiercely." (Ch 2)
In chapter 3, Jack becomes obsessed with, "The compulsion to track down and kill..." to the point that it is "swallowing him up." Whilst talking about his attempts, "The madness came into his eyes again." Jack and Ralph clearly have different agendas and "the antagonism was audible." It is becoming more difficult for them and they are "unable to communicate," when it comes to the importance of building shelters (Ralph) and hunting (Jack).
Painting his face is the real turning point for Jack:
He looked in astonishment, no longer at himself but an awesome stranger...He began to dance and his laughter became a bloodthirsty snarling...the mask was a thing on its own, behind which Jack hid, liberated from shame and self-consciousness..." (Ch 4)
Everything has changed. Jack allowed the fire to go out in his excitement at killing a pig. Some of the boys are in awe of him and this encourages his behavior. Even when Jack speaks without the conch, Ralph can no longer exert his authority and in chapter 8, Jack will split from "Ralph's lot." He even suggests that he may consider allowing Ralph to join his "tribe" and the fact that Ralph and Piggy actually accept meat makes Jack proud. When Simon appears, Jack can no longer distinguish between reality and this frenzy and, after Simon's death, nothing can stop Jack. Later, Jack is more affected by the smashed conch than Piggy's death, feeling victorious. Ralph becomes no more than a hunted animal.