[yokai]

Linked to portfolio, which contains all of that.

Most people don't bother with that, hence the direct link instead. (Or a side by side comparison would be even better,)

Only drawn on paper and that's it.

Well to be painfully accurate here, you would need to first draw it for hand, then scan it into your computer to get it digitally. (Or take a hand image of it, but that might look awful.) That and this image was originally drawn on white, so you did do some after edits in the terms of changing the background color and adding some slight effects to it seems. (Vignette and noise.)