The real thing about evil," said the Witch at the doorway,....

“ The real thing about evil," said the Witch at the doorway, "isn't any of what you said. You figure out one side of it - the human side, say - and the eternal side goes into shadow. Or vice versa. It's like the old saw: What does a dragon in its shell look like? Well no one can ever tell, for as soon as you break the shell to see, the dragon is no longer in its shell. The real disaster of this inquiry is that it is the nature of evil to be secret. ”

Gregory Maguire

From : Wicked: The Life and Times of the Wicked Witch of the West