At the beginning of my career as a comic artist (in the early 90s) I illustrated the covers of a horror comic, so when someone asks me for something related to demons or with a horror theme it’s a bit like going back to the origins 🙂
In this case the client simply wanted something demonic.
The initial idea was that of Lucifer sitting on a throne made of skulls with the souls of the damned squirming below him, but as soon as I began working on the design I realized that the available space was too small for that particular idea. A project of such intensity was more suited for a back piece.
So I focused myself on other options. 
I made four very rough drafts to give the client an idea of what I had in mind and from those he chose his favorite one.
So all that remained was to work on the design and translate it on skin.
It would have been nice to develop this work on a larger surface but there will be time for bigger projects too 😉