This, too, was myself. It seemed natural and human. In my eyes it bore a livelier image of the spirit, it seemed more express and single, than the imperfect and divided countenance I had been hitherto accustomed to call mine. And in so far I was doubtless right. I have observed that when I wore the semblance of Edward Hyde, none could come near to me at first without a visible misgiving of the flesh. This, as I take it, was because all human beings, as we meet them, are commingled out of good and evil: and Edward Hyde, alone in the ranks of mankind, was pure evil.
Robert Louis Stevenson, The Strange Case of Dr. Jekyll and Mr. Hyde
duality, evil, jekyll-and-hyde, mankind