A few Thoughts on why Shaara titled his historical fiction: The Killer Angels.
The title originates with an incident in Chamberlain’s childhood. Quoting Shakespeare to his father one day, Chamberlain delivers the lines, “What a piece of work is man . . . in action how like an angel.” When his father reflects that if man is an angel he must be a murdering one, Chamberlain is inspired to prepare an oration for school on “Man, the Killer Angel.”
Later, in conversations with Kilrain, a former sergeant in his regiment who is like a father to him, Chamberlain discusses his thoughts on the nature of man. Chamberlain sees each man as equal, possessing a “divine spark” that separates him from animals. Chamberlain is an idealist who still sees man as an angel. Kilrain, however, sees many a man as having no more worth than a dead dog.
At the end of the story, as he looks out over the field of dead bodies, Chamberlain remembers Kilrain’s words and thinks back on Killer Angels. Chamberlain realizes he cannot agree, feeling strongly connected to all the men that day, regardless of side. He concludes instead that at least in the sight of God, they are all equal now.