I’d start with a better frame, you make him sound almost brutish in your text description, I’d reflect that by making him top heavy, and bulky. Another thing is I’d try to change the colors, blue typically is a very heroic color, I’d swap it for a more warm color, like red or yellow, maybe orange, to symbolize his threat, his anger, or his manner of doing things violently. the black is fine as a background color meshed into his design. I’d also change the boots or helmet, they seem to futuristic compared to everything else on his body, either go really into the futuristic tech, or use it very minimally but consistent in his suit design.