Btw, most fantasy games, anime or whatnot with their own fictional world, as a whole, are very often even not as wide as a single real life continent. The scale of our 'little' Earth is actually a whole lot bigger than what most people could imagine (and thus translate correctly to fiction) even when we already have a world map and a globe. And now we have a star sized planet? My disbelief is in a very tight suspension there
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Aside from alternate history, ASB and their variants, I don't think I remember having seen a fantasy world even as wide as our Earth. The most probable reason for it that I can think of is the lack of content to fill in a space that large.