I can definitely see Sicarius as an artist. Lovely idea!
Well, I can talk about my thought process since I'm not sure I'll get to detail it in the fic. Seeing how Sespian has an interrest for architecture and he takes his artistic abilities seemingly from Sicarius, I wanted Sicarius to be an architect in my parrallel universe. But then, Sarah mentionned that in a society like Turgonia, architecture and engineering were probably one and the same (as it was here until the 18th century). Then, since Sicarius had told Am that he dreamt of being in the military as a kid (well, an admiral, but let's go with military more generally) I came up with the engineering corps bit. We know they exist since Tikaya thought Rias was one before realizing he was Admiral Starcrest.
So, he's now a decommissioned Engineering Corps officer that works as an engineer/architect for a firm in Stumps and draws/paint in his free time (from there the fact that he's in the park early in the morning, before he goes to work).
I also got a few more background surprises in store. As I thought, the monster plot bunny got me and I'm now trying to figure out how to introduce at least some of the EE gang and how Sespian would still exist in that world. Oh, and Pike is still a piece of s***t.
Also, not sure when part 2 will be posted, I still need to finish up my personnal prject and write down my Santacarius. Also, I promised a few people that I'd finish Romance and Mayhem, so ya... lots of projects, too little time.