According to Rowling , one of Harry 's pivotal scenes came in the fourth book when he protects his dead schoolmate Cedric Diggory 's body from arch villain Lord Voldemort , because it shows he is brave and unselfish . According to Rowling , one of Harry 's pivotal scenes came in the fourth book when he protects his dead schoolmate Cedric Diggory 's body from Voldemort , because it shows he is brave and unselfish .