I've seen this done before, and I had a feeling one of my tumblr followers would enjoy it a lot - so we have Tom Hiddleston and his dark alter ego, Loki.
I had loooooads of problems with this sketch. The other fineliner I was using is thick and goes a bit fuzzy when I use the blender pen, so I found another one. This one smudged really badly though, which I'm quite annoyed about, but I thankfully managed to salvage most of the image. It might be because I didn't leave it to dry long enough, so I may try that in future, or just use it to highlight details after I've done the copics work.
*rolls around in artistic anguish* ah well, you live you learn.