So the castle is a mirror, a distortion of reality. Thus, whoever signs the contract would, in actual reality, have their souls with whole mana intact be stripped away from their bodies. And once they enter the castle they will be stuck in a loop inside the building's reflections, maddening them to the point of submission, allowing the Fae to rewrite their fully emptied souls to whatever they please... If we apply Rainburn page 350 to the equation (call me crazy I know).
The Fae are demonic entities!!!
