I have spent a lot of time looking at both other posts on this form about derivative work and its actual definition/ conditions, but I would like to hear your thoughts on this specific case. I have been working on an RPG rulebook from scratch that happens to revolve around a similar setting to the Shadowrun RPG. Both settings revolve around a party of mercenaries in a cyberpunk future where magic has started cropping up. Though the flavor of magic I am using is much more dark fantasy/Lovecraftian than Shadowrun's generic high magic, I am not sure if having many elements from Shadowrun's setting makes this a derivative work.
Mechanically, all the rules in my RPG are original and quite different than Shadowrun, but because of the similar setting, many of the rules cover the same topics (such as hacking and drones).
I am considering (but not set on) trying to sell this RPG for a small amount of money at some point in the future, which, as I understand it, may make derivative work a real issue If I don't pay attention to it. Do you think this constitutes a derivative work?