Am I at legal risk if I use a mechanism from another game in my own design?
Disclaimer: I am not a lawyer


This answer* on startups.SE suggests (though doesn't completely confirm) that the mechanisms of a board game cannot be patented (which I suppose explains why we have so many deck-builders, for instance), but you may be at risk of copyright infringement if you go so far as to copy graphics, trademarked characters or names and copy used in the rulebook.

It goes without saying that since you refer to a "popular fantasy universe", you may have more to worry about from them than from Steve Jackson if you intend to use existing characters etc.

Given that, I think that using a mechanism from another game is acceptable.

*The linked question is about an electronic adaptation of a board game, but I believe the answer still applies