Well its not bad. Somethings I would work on: -Crop it the top half is just blank -Try to draw the legs, I know you said it's not your strong point but it's always fun to practice and get better. -Some better shadding would be nice.
600 pounds? I understand he is "half oni" but that's a bit much for Mr. Shaved Nipples. Doesn't look 8 feet tall or 600 pounds, sorry, you're character bio killed it for me. I like seeing full standing sketches of character concepts but I suppose its not bad.
the main problem i see with this piece is the arm muscle placement. The bicepts are pointing in, and if you look at yourself when you stand in front of a mirror, they face outward, or straight out, the reason you probobly have trouble drawing hands is its almost impossible to draw them normal with the bicepts straining inward like that.
soso. i like the way u drew the face...but the arms killed it totally. o and btw u should try and draw him in a more realistic pose...it looks like he is flexing or something with his arms out like that.