Thank you. The geek-friendly part made me very happy.
My process may be quite awkward at times, but actually this was a very straightforward piece. It’s just an ink drawing with an overlaid color layer, both done on separate sheets of paper, then merged in photoshop. This picture I posted in Instagram will maybe help to answer your question:
I did the colors using markers as you may see. As for the splattered effect you see in the background, I used a tool called Letrajet which is supposed to turn your Letraset Promarkers into “air markers”. It’s sort of a toy, really, and (at its best) it may act as if you’re using a damaged airbrush. But I still use it sometimes to get that sort of lo-fi effects. I’m not sure if they still sell it, but unless you’re some sort of marker nerd, I would emphatically recommend getting a cheap airbrush instead.