I bought this miniature at a flea market along with several others, and was wanting more information on him so I can be more accurate with my painting, and market him better.
The only info I have is what's stamped on his bar - "Chaos Warrior" on the front, and "GW 1988" on the back. My best guess is that the "GW" stands for Games Workshop, most likely making him a Warhammer 40k mini. That's just my guess. Any more information would be helpful, even if it's only a guess.
Here's the picture I have of him right now. Its not the best, but I'll upload a better one when I find my camera cord.