30 points. The demon lord being human alone would not be enough reason for Dylan to quit. One piece of information she may be unaware of that limits her understanding is that he kept in contact with the king through reports. If Dylan divulges that, she should be able to link his reasons to the politics and proxy battles between countries. Or in other words, he called BS on the whole mission, and refused to be a pawn.
This is not spoilers, this is a play-by-play of a battle of information. Any amount of extrapolation relies on making certain assumptions, thus can be entirely barking up the wrong tree.