list of worldbuilding ideas i have right now (mostly in response to questions)
-I'm thinking maybe there's two 'species' of mermaids. The distinction is in the tail strokes; one species moves with horizontal strokes (like fish) and the other with vertical strokes (like mammals). Horizontal strokes are more common I'd imagine.
-I also noticed that everyone's mermaid art seems to have a slightly differing idea of what features mermaids have (such as fin ears and colored sclera), so perhaps there's a few vestigal traits from when mermaids were more fish-like that certain regions + families hold onto? also, i feel like there's a word for this, but there's a genetic thing where a creature can be born with extinct traits randomly reappearing after centuries of not occuring, ex. whitetails with fangs and birds with small teeth. so perhaps these could also be 'evolutionary throwback' traits.
-on that note, Space Man gave me the idea that the mers are so human-like because they evolved that way to prey mainly on humans. However, because humans have become so technologically advanced, they've now switched focus on what they eat and prefer to avoid humans now. so maybe vestigal traits from when they were more fish-like are now coming back and serving a real purpose again. like they're devolving
-when it comes to tail species, it could be a trait that varies in the same way hair and eye color do, and the resemblances to fish species is mere coincidence shaped by their environment and genetics. i don't know about this though
-i was thinking about what their currency would be, and i think maybe seashells and sea glass could work? the only issue i have with that is sea glass comes from humans and isn't a reliable source, and seashells are Everywhere. perhaps the only seashells that count as currency are ones that have been painted with a specific hard to reproduce paint. and maybe seaglass works as currency because it's just valuable as it is.
-for clothing, i think mers usually go for plants they weave together and nets they can scavenge or create themselves. maybe leather from water mammals too, such as seals and dolphins and the like, though the leather making process can be a bit difficult since they need a good beach to work on. Human clothing is usually automatically viewed as a more higher class thing since it's such a rarity for it to drift down to their level.
-they do utilize dolphins as pets, mostly for disabled mermaids who's tails may have been wounded by boats or other sea life. dolphins are like their service dogs since they are so intelligent.
-going back to the Mermaid Sewed Together Biology. i don't really know how they breathe 💔 the noses could be a false thing that was only evolved to bear more resemblance to humans and they really have gills, or maybe they have to surface every few hours for air.
-that's all i got right now, i may add to this later
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EDIT more ideas I had that I forgot
-I was looking at sea parasites, and there's a type of barnacle that targets a very specific species of crab. anyways this gave me the idea that barnacles could be some sort of parasite disease they can get. to make the ocean feel a lil more scary for them.
-since they live underwater and have human level intelligence, I don't think they would solely depend on human ruins sinking below the sea to inhabit. i think they try to guide coral into specific shapes, scavenge materials from whale bones, and use volcanic rock from underwater volcanoes as their most common building materials. also i think a lot of mermaid settlements are located near reefs or volcanoes - reefs because it offers food and protection, volcanoes because it deters foes and they can use the materials. Ex. using volcanoes for blacksmithing and such (technically they don't get hot enough for smithing but mermaids aren't real either soo). credit to Moff for the volcano idea
-for drinks, i think that was a concept invented by humans and now routinely stolen from humans. they're under water so they don't really have anything driving them to drink, but it's a fun taste, and when they're sunning on beaches, a quick sip of something can help them stay hydrated and thus stay in the sun longer. silly idea maybe the only reason they lure ships in anymore is to ask them to toss some drinks down
-i need to think of the kingdom of Neralos itself more but bleghh... plot relevancy... i'm better at small useless details. I think Neralos is in some Unspecified Location in the Pacific or Indian Ocean. There's a small island there that has somehow avoided discovery with nice sandy and rocky beaches. The reef itself is very large, having been cultivated and nurtured by the mermaids that live in it (mermaid architecture and farming kind of go hand in hand). the castle itself i have very few ideas for, i just know that it's most likely mainly made of coral. definitely near a volcano, it's a kingdom after all so they need their own forge.
Spring Month: 2 
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Flood Moon: 
