Unsounded/Fridge

Fridge Brilliance

 * Duane's face looks almost human when the story begins, but becomes grayer and more run-down as the story progresses. This is because his glamour is slowly failing due to an increasing lack of beauty to draw from, and also because of psychological complications (he hates it, since it's like he's living a lie). Confirmed by Word of God here.
 * Also, Duane's glamour that makes him look like a normal person breaks if you look him in the eye. Why? Because Duane's too honest for his own good, and he can't lie to you if you're looking into his eyes.
 * And adding on to that, when is the only time when the viewers are able to see Duane's true face? When we can see his eyes.