You can definitely tell Kuroeda is one of the author's favorites lol. Just cant resist drawing that ass in almost every arc. She almost has as many appearances as the MC elf girl. And that only cause shes the MC.
Throwing my vote in with @CelticMutt on them being Naga. They are dark skinned with long black hair and have a forehead dot very similar to a Bindi; that suggests Indian to me or at the very least Hindu.
@SSJR2 Well, the author is a self proclaimed ass man. When someone asked him his preference, he answered like this (from his now defunct Tumblr): https://danbooru.donmai.us/posts/2491380
Nothing brings me more delight than just how MANY kinds of thicc this artist has filled this manga with and also manages to draw in dynamic poses and motion.
Aside:
(This makes the fact that the only h-doujin of this I've seen reduces most of them down to fairly standard-sized elves a damn crime)
Also, the fact that whatever signs Potato is giving is elaborate enough that it can include an insult is pretty amazing.
@maximuffin2 I think you underestimate the power of niche audiences in Japan, a country where Hisone to Masotan isn't even the strangest show out there. 😛