Answer:
My teeth are sharp, my back is straight, to cut things up it is my fate.
Scythe of darkness, Shadow’s light. Guiding eye of thirteenth sight.
It happens when something has been cut with H2O.
Two horses, swiftest traveling, harnessed in a pair, and grazing ever in places. Distant from them.
Look into my face and I'm everybody. Scratch my back and I'm nobody.
What gets broken if it’s not kept?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?