Who is Roland Croninger from Swan Song and what is their importance?

Roland is an average boy in the beginning of the novel. He is restless after a long car trip and plays a little too freely with his father's gun, carelessly tucked under the seat. He idolizes Colonel Macklin, war hero of Vietnam, and enjoys playing a game called King's Knight. However, Roland is different from the average child, apparent immediately when he crushes the butterfly in his room for no reason. He has a capacity for great evil, but perhaps if the future had gone differently he could have learned to lead his life in an a way that caused no harm.