Answer:
When you take away the whole from me there is always some left.
A dragon's tooth in a mortal's hand, I kill, I maim, I divide the land.
I have two bodies joined together as one. When standing still I run and run.
Ten men's strength, ten men's length. Ten men can't break me, yet a young boy walks off with me. What am I?
Use me to reward good behavior.
I am always hungry, I must always be fed. The finger I lick will soon turn red. What am I?