In a fantasy world filled with magic and miraculous beings, will the religious concepts of the locals be completely different from the human of Earth?

[Sepulchrave II]

I've not read serious biographies, but I assume that Bentham and Mill were atheists. Presumably also the Wollstonecrafts. And Hume, of course (I mean perhaps in a technical sense he's an agnostic, but in every day terms . . . )

Mary Wollstonecraft was definitely a deist, or a rational theist - she often framed her feminist arguments in religious language. Although she despised the clergy and superstition.

Mill called himself a “non-believer” but was not militantly atheist. In Three Essays on Religion, he allows that a benevolent deity is “not inconsistent with the facts of nature,” though he rejected orthodox Christianity. Bentham, was definitely more hardcore atheist, although even he occasionally uses deistic language.

Hume didn’t write anything explicit, but that might have been due to Scottish blasphemy laws. Boswell notes that in private, Hume was an atheist.

But I think it was the Germans who really smashed it all up.