Answer:
What has one eye but cannot see?
Flat as a leaf, round as a ring. Has two eyes, can't see a thing.
What kind of nut is empty at the center and has no shell.
I cut through evil like a double edged sword, and chaos flees at my approach. Balance I single-handedly upraise, through battles fought with heart and mind, instead of with my gaze.
There is an ancient invention. Still used in some parts of the world today. That allows people to see through walls.
The strangest creature you'll ever find: Two eyes in front and many many more behind.