[Doskious]

Full Disclosure: I do not own the relevant sourcebook, the "Niobe Pathfinder Module".

That being said, I have it on very good authority that, just as with every publication for Pathfinder 1e, there can be found at the back of the book the OGL itself following the standard statements about compliance and the designation of "Product Identity" and "Open Game Content" -- the Open Game Content definition specifies "game mechanics" as is standard in that section, and nowhere in the subsequent copyright designations is anything presented that, in my (#notlegaladvice, #iamnotalawyer) personal opinion, could even unreasonably be interpreted as applying to the Omdura class.

As such, the game mechanics of the class would seem to be fair game for replication, adaptation, and circulation. (Note, if there is an issue with the class name potentially being "Product Identity", it's trivial to rename the class without altering the mechanics, which are very obviously covered by the OGL.) This being the case, I've attached what I believe should be a fully-functional Omdura class definition.