Who is Christopher Harte from The Pact and what is their importance?

Christopher Harte is a seventeen-year-old boy when the book opens. Through the course of the novel, however, the reader gets to see Christopher at different phases of his life. Chris lives with his parents in a small town in New Hampshire. Next door, lives another family, his mother's best friend, and their daughter, only three months younger than Chris. Chris and Emily grow up together, best friends, never apart. When one falls, the other bleeds. Together they grow and mature, eventually blossoming into mature teens, who find intimacy with each other the same way they discovered all else about life.