I did several things to your logo.
First I bumped the contrast between colors way up, and added a blue cast to the shading to match your lineart a bit.
There was also a lot of unnecessary noise that wasn't really defining anything, so I began simplifying all the shapes. I didn't know which direction your lighting was coming from so I decided to light it from the bottom, because that seemed appropriately dramatic for a Medieval themed game.
I also did some fixes to his hands, unless he's supposed to have only six fingers... maybe.
I also rounded him out and made his muscles more organic. You also might want to try define them a little more purposefully. Super muscles aren't my strong point, so I didn't try to mess with them, but some of his arm muscles look more like deep pock marks at the moment.
I also did a scary face edit... hmmm, because? I really like his current face... but his posture suggest something more aggressive. His current face is rather benign.
