Answer:
My first is high, My second damp, My whole a tie, A writer's cramp
There is an ancient invention. Still used in some parts of the world today. That allows people to see through walls.
Both punishment and sweet reward, It will befall both fool and lord. It is a spiritual scoreboard, Your every deed it does record.
This is in a realm of true and in a realm false, but you experience me as you turn and toss.
I cannot be other than what I am, until the man who made me dies. Power and glory will fall to me finally. Only when he last closes his eyes.
Special abilities and brightly colored underwear are all you need to be one of these.