Answer:
Held firmly in the hands, like a sword it cuts deep. Bloodless strokes, all, then forward we leap.
I am believed to be only one dimensional, and tinier than anything can be, and there are many who say that I am the basis of all that we see. What am I?
It can pierce the best armor and make swords crumble with a rub, yet for all its power It can't harm a wooden club.
At the sound of me, one may dream or stamp their feet, At the sound of me, one may laugh or sometimes weep.
What is eaten but not grown and was born in water but will disappear if soaked?
I am your mother's brother's only brother in law. Who am I?