[krapp]

>This seems to point at a bigger issue where the black creatures are considered foul?

Likely in part due to J.R.R. Tolkien's influence on Western fantasy archetypes. Almost invariably, his books equate light skin with purity, civilization and goodness, and dark skin with corruption, barbarism and evil. Not to say that he was racist in the same way as H.P. Lovecraft was when writing about fish-men from Innsmouth as a thinly veiled metaphor for race-mixing, but rather that given Tolkien's Colonial British upbringing, he may have been blind to his own cultural prejudice.

Over the decades this has sort of become a trope that has seeped into a lot of fantasy and even science fiction.

[BoiledCabbage]

I think you hit the nail here. Racism is broad term, and there is the direct individual Lovecraft style racism, and there is the other which is not as overt but has merit. An example is that idea that black is often time given connotations of brutish, evil, selfish, ...

While white is described as representing "morality, order, community, civilization, ..."

Are they the same, of course not, but we also can't say it has no significance either, as it does to always have those associations.

[b0rsuk]

I dunno, maybe because many things turn black when they rot? Doctors and scientists dress in white or very light colors simply because it makes stains very visible, and it makes it easy to keep clean. I even asked a gay man why do they like white panties and socks so much and he said just that - it's a visible testament of hygiene.