Oh? Lucifer is normally careful how he shows expression, to keep his emotions under control, unless pushed too far by his brothers... but right now, facing away from Conrad, his eyebrows go up in surprise with that reveal. The sinners could take on demonic features?

Interesting.

"The more we sin the more demonic we become?" What would that mean for him? He's already a demon lord, already had his true demonic form. If he continues to spite the God of this realm, would he gain more? In a manner... Lucifer isn't against it, if it shows his distaste for God, however... his vanity would only want something that would compliment his appearance.