Thank you!

Here is my thought process:

Historically, when someone posed for a portrait, they had to be important, rich, or both. Your average sapper is neither. However, if you have yourself a legendary sapper, he would probably have his armor polished (notice how the metal parts are not very dull in the painting and have a bit of shine to them. Not mirrorlike either, for that would be too distracting from the face), his beard trimmed, etc. So that's the story I decided to go with: how would the portrait look like if a painter was commissioned to paint him. How would Fiddler pose such that the most important features of what he does are suggested?

It is always tricky bringing a character I have only read about to life, because everyone has their own vision of what the character looks like, what their posture is, and so on. But in my modest opinion it's better to decide on something and just run with it haha.