OK, I was thinking a bit more about this and what people might populate the Hollow World.
Pretty much the same as 3e’s Oriental Adventures but with a couple more – Korobokuro, Rakshasa, Vanara, Spirit Folk, Nezumi, Hengeyokai, Yakfolk/Minotaur, Loxodon.
I want to come up with a multi-armed human variant too. That’s in the works now.
Luckily most of the classes copy fine with minimal tweaking.
As for the rest of the world, I’m thinking prehistoric creatures like mammoths and woolly rhinos, various types of dinosaur, giant bugs, that kind of thing. Can probably throw in weirder stuff too, like Yeti, giant six armed white apes, hopping vampires, or sky whales.
Yeah, think this is sort of clarifying into something now.
I really have too many settings to think about…