Hmm difficult to crit, since it’s still in an early state. Where to begin.. determine light source. Since this is going to be sketch we don't have to worry too much about the type of light source but the direction and color would be very useful I believe. Also will it be soft or hard light etc. Since it is a demon will the skin be rough, soft or shiny. Those were the first questions that came up in my head. Hmm don't know or this is of any help at all, perhaps tell us some more about your idea so we can help you with your goals
. Calibration is always such a pain in the *ss. Hope you laptop will be fixed soon, cheers!