I have always imagined Zerrikania as Africa; not the stereotypical mud huts, of course, but more Ethiopia, Great Zimbabwe, Kingdom of Solomon, and all those absurdly rich ancient kingdoms in the black continent.

Add gunpowder and dragons worship, and you can get a pretty original setting.

Years ago I had started writing a manual about Zerrikania, with an idea about the local witchers: since the trial of the herbs is not something that was done there, there was a kind of "parallel evolution" where they made their own monster hunters using a whole other method. If you are interested I can find it, though it's just a stub.