awesome job first of all, i am not yet near your level but i will try to see if i have something to help.
I think the right hand of your character hiding behind the body, it is not really obvious what is supposed to be doing. i think the rightshoulder needs to be a bit further back for the hand to come in at that angle or your forearm is a bit too short. Or the hand is too big, it reads a bit confusing for me in that area.
the right chestmuscle folds beneath your rightarm, so it should follow that instead of going up towards the collarbone.
I could be wrong though, so if anyone could confirm this that would be great. Or you could check for yourself.
Maybe also write down what your doubts are about the character or what you like to improve , or what you like to have critiqued.
i like the tattoos a lot and how you textured the muscles of the character.
Great character overal, would like to see him in more threatening poses as well 
I hope it helped somewhat atleast.
Good luck!
