Kobold Avenger
Legend
Previously only Humans were ever shown as being non-European in D&D, and the other common core races of Elves, Dwarves, Gnomes and Halflings were always depicted as being "white" even if some published campaign settings have for example said that some Dwarves have brown skin or that Wood Elves are "bronze" colored. Now I pick those four in particular because they're the most human-like (not counting the hybrids) and they're a core part of D&D along with all the classes and alignment, it's generally assumed they're there unless the DM says they aren't.
So if a player wants to play an "Asian" Elf or a "African" Dwarf, I suspect most DMs in most campaigns would just let them be with very little questions. It doesn't necessarily need to be fully explained why that Elf or Dwarf is like that. Some people might just want to have character who might be like them, or might fit some image they have (or justification for a class/subclass with a lot of cultural baggage). I'm approaching this as a Person of Color, who is a minority in the western country I live in. So I care less about cultural purity, and more about representation.
Dara from the Netflix adaptation of Witcher as an example.
But for others DMs they have to work in something. Are Halflings and the others for example as widespread as Humans are in that campaign world, virtually living everywhere that Humans do? If so then yes. This would in many ways be the Shadowrun approach, which conceivably Shadowrun might be the first RPG where "metahumans" of different ethnicities are a canonical and established thing where a Dwarf could be from Shanghai and an Elf could be from Nairobi.
But there also could be something like for example, where at one time there were different cultures and ethnicities of Elves (not counting subraces) but they moved around a lot and mixed, such that there is no real distinct cultural differences in Elves anymore. A lot of times the assumption is that they somehow default to a European culture, though Eberron has an Elven culture that's sort of has a bit Arabic influences, and another that has African and other influences.
Now the idea of Elves, Dwarves and Halflings in D&D of course comes from Tolkien's work. Despite Elves and Dwarves having origins in Germanic myths, Elves as commonly depicted in fantasy are sort of the Aos Si of Celtic myths, and despite the fact that Tolkien tried to depict Dwarves as being Jewish they somehow commonly became Scottish (someone once joked what if Dwarves were Mexican). Halflings (as Hobbits) are mostly original to Tolkien's work but sort of represented the humble Englishman, and Gnomes were first mentioned in the Renaissance and somehow became a caricature of Jewish people. But despite all this, they are a core part of D&D's identity among the core assumptions about most D&D campaigns.
Some settings which attempt a deep-dive into certain Earth cultures assert that there are none of those core races in the setting (but there may be local alternatives), because there's no myths about such things and cultural purity would be more of the goal. And that's fine if it's the primary setting and focus of the campaign. But in a campaign that's a lot more international where there are various "expy's" various Earth cultures living on the same world and the PCs could be from anywhere, then this is where the question of "could gnomes be from over there too?" In terms of world-building it's likely easier just to have Gnomes there, with some sort of parallel culture to the region. They may be of the same subraces as Gnomes in the PHB, but there could be some sort of local Gnomish subrace for the region. Having a completely different race in place of Gnomes everywhere else, might be too much work for many. And if there are for example regional races like Hengeyokai to use an example, then why aren't they in other places?
So back the original point is that overall I feel that Humans should not be the only race with diversity as its thing. Despite whatever the origins of Elves, Dwarves, Gnomes and Halflings, in core D&D they are now far removed from their mythological Earth origins, so they don't need to be locked in as exclusively European.
So if a player wants to play an "Asian" Elf or a "African" Dwarf, I suspect most DMs in most campaigns would just let them be with very little questions. It doesn't necessarily need to be fully explained why that Elf or Dwarf is like that. Some people might just want to have character who might be like them, or might fit some image they have (or justification for a class/subclass with a lot of cultural baggage). I'm approaching this as a Person of Color, who is a minority in the western country I live in. So I care less about cultural purity, and more about representation.

Dara from the Netflix adaptation of Witcher as an example.
But for others DMs they have to work in something. Are Halflings and the others for example as widespread as Humans are in that campaign world, virtually living everywhere that Humans do? If so then yes. This would in many ways be the Shadowrun approach, which conceivably Shadowrun might be the first RPG where "metahumans" of different ethnicities are a canonical and established thing where a Dwarf could be from Shanghai and an Elf could be from Nairobi.
But there also could be something like for example, where at one time there were different cultures and ethnicities of Elves (not counting subraces) but they moved around a lot and mixed, such that there is no real distinct cultural differences in Elves anymore. A lot of times the assumption is that they somehow default to a European culture, though Eberron has an Elven culture that's sort of has a bit Arabic influences, and another that has African and other influences.
Now the idea of Elves, Dwarves and Halflings in D&D of course comes from Tolkien's work. Despite Elves and Dwarves having origins in Germanic myths, Elves as commonly depicted in fantasy are sort of the Aos Si of Celtic myths, and despite the fact that Tolkien tried to depict Dwarves as being Jewish they somehow commonly became Scottish (someone once joked what if Dwarves were Mexican). Halflings (as Hobbits) are mostly original to Tolkien's work but sort of represented the humble Englishman, and Gnomes were first mentioned in the Renaissance and somehow became a caricature of Jewish people. But despite all this, they are a core part of D&D's identity among the core assumptions about most D&D campaigns.
Some settings which attempt a deep-dive into certain Earth cultures assert that there are none of those core races in the setting (but there may be local alternatives), because there's no myths about such things and cultural purity would be more of the goal. And that's fine if it's the primary setting and focus of the campaign. But in a campaign that's a lot more international where there are various "expy's" various Earth cultures living on the same world and the PCs could be from anywhere, then this is where the question of "could gnomes be from over there too?" In terms of world-building it's likely easier just to have Gnomes there, with some sort of parallel culture to the region. They may be of the same subraces as Gnomes in the PHB, but there could be some sort of local Gnomish subrace for the region. Having a completely different race in place of Gnomes everywhere else, might be too much work for many. And if there are for example regional races like Hengeyokai to use an example, then why aren't they in other places?
So back the original point is that overall I feel that Humans should not be the only race with diversity as its thing. Despite whatever the origins of Elves, Dwarves, Gnomes and Halflings, in core D&D they are now far removed from their mythological Earth origins, so they don't need to be locked in as exclusively European.