Jack's dominant character traits include his savageness, aggressiveness, and his malice. "This head is for the beast. It's a gift." (Jack, Page 137) "You and your blood Jack Merridew! You and your Hunting! We might have gone home-" (Ralph, Page 70) The author, William Golding, portrays Jack as a savage and very instinctual character who quickly resorts back to a human's true savagery since being stranded on the island and leads his "hunters" and other followers down the same path. I think it's a little crazy how quickly Jack turns on the group and loses sight of their real goal: to survive on the island together until help arrives.
Ralph's dominant character traits include his leadership abilities, virtue, and care for others. "Don't you all want to be rescued?" (Ralph, Page 102) "He noticed Ralph's scarred nakedness, and the sombre silence of all four of them." (Jack, Page 70) The author portrays Ralph as a very serious person who leads the islanders and is primarily focused on getting home. I see Ralph in a very similar sense and I think he was a great leader for the rest of the island and stays on task throughout the whole book unlike Jack.
Piggy's dominant character traits are that he's smart, caring, and witty. "We was scared!" (Piggy, Page 156) "I can't think. not like Piggy." (Ralph, Page 78) Golding portrays Piggy as a smart, chubby kid who is always getting picked on by people like Jack and his followers. He is caring and sticks with Ralph throughout the book. Based on how Piggy is and how he's treated by Jack right away, I imagine he was treated similarly by others at home by people who never really got to know him like Ralph.