The perfect killer has no identity.
“Why is it, my shadow-striding friend, that we don't fear dreams? We lose consciousness, lose control, things happen with no apparent logic and abiding by no apparent rules.... We don't fear dreams,...”
“Tell them the Night Angel walks. Tell them Justice is come.”
“My question is, do you believe in an evil possessed of its own purity? or does every act intend some good?...”
“The truth." Dumbledore sighed. "It is a beautiful and terrible thing, and should therefore be treated with great caution.”
“The truth is rarely pure and never simple.”
“Never tell the truth to people who are not worthy of it.”