Answer:
I don't currently have the book with me so I can't cite atm :/ but I would describe piggy as more of a follower of a group but someone who also isn't afraid to speak out. I would also say he may be one of the weakest in his group because he's not physically fit and his asthma. You could also describe him as an easy target for the rest of the group to pick on. Throughout the book though piggy follows ralph around while helping to problem solve. I bet you can pull out some random quotes from the book from when they first describe piggy though :)