If you are brave enough with a pure heart, you will be able to enter the castle and inside it, there will be a throne. On the throne, there will be a man with no clothing but a human skin draped across his old and aged body; he will ask you a single question.
Should you answer it correctly, you will ascend past physical form and gain knowledge that the man on the throne has. But be careful, the castle will collapse as millions of souls will be released from his cruel grasp; their moaning will be overwhelming and thunderous, the man will turn to ashes and a scream will fill the putrid air around you.
Should you escape, you will be the most powerful creature in the world...
The only catch is that you will not be able to speak to any human after this and your soul will be as cold as glacier ice.