Shane was the original bad ass. The group would be much different if he were in charge (being dead sort of changes that)
In the graphic novel, Ben was the twin of Billy, his brother. He was a budding serial killer that killed animals and such for amusement and then one day lured his twin brother in the woods and killed him with a knife. It was a pivotal moment in the book because the group was horrified by it and knew no one was safe around him. Almost everyone wanted to kill him, but no one wanted to come out and say they should kill a small kid. Carl later slipped out in the night and shot him.