The definition of the muscles are nice however it
seems as though you have strayed away from the original concept
a little. The character now seems stocky and almost "dwarfish" compared
to the gangly, "golem"-esque like characer in the concept.
I would expect the pawn piece in chess to be a weak piece, but in the right
hands it could surprise and frustrate your opponent. I think you need to emphasize this more in your character. Show it as something initially perceived as weak but with the power to surprise.
Proportionally, give it longer legs. Perhaps a more anorexic appearance which would complement a ferocious and hungry facial expression.
Again, look at Golem (LOTR) for reference. Good luck.