I am not sure how Judaism fits on the Discworld, but if you have figured it out, I would love to know.

(Not that I'm sneaking through your letter or anything, but there's a kosher butcher in Ankh-Morpork mentioned a couple times (in Feet of Clay and Unseen Academicals, maybe also elsewhere?). IDK if Terry Pratchett ever thought it through that it meant there were Jews in Anhk-Morpork, but he put them there.)