Answer:
With three eyes and as black as night I frequently knock down ten men with a single strike!
I have leaves on my fruit my fruit is on my leaves.
Can not be bought, Can not be sold, Even if it's made of gold. What is it?
The more you take the more you leave behind. What are they?
Use me to reward good behavior.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.