Grey, looks good as grey I think at this point. Maybe push some of the darker shadow areas a little darker, but make sure you keep in mind "shadow" and light source. "Black Skin" might overwhelm it. Do it grey scale, slightly pushing some of the shadow areas considering how the light is hitting the figure. Then when you're done rendering it greyscale, do hit me on chat, and I'll give you some tips as to how to add even more magic. kk.