Atluden

Atluden (singular: "Atlud") are an ancient kind of Merfolk, by many cultures believed to be the "First People" because of morphological and linguistic similarities with many cultures.

Hemo-pneumatic System
Atluden are aided in breating not only by their skin, but also by a dual respiratory system: they have lung cavities like humans, but also sport gills on their neck, ribs and shoulders, which can all be retracted into the body when out of the water to prevent essiccation. During these periods of dryiness, these cavities can also hold a small amount of water for allowing some respiration, although very limited. This system is akin of the ones in arthropods like crabs.

Atluden blood is bright purple/fucsia (sometimes more blue, sometimes more red depending on the individual), and is functionally between mammal blood and horseshoe crab blood, having both hemoglobin, red, like mammals, and hemocyanin, blue, like octopi and horseshoe crabs. With these last ones they also share important immune cells that are exceptionally sensitive to toxic bacteria. When those cells meet invading bacteria, they clot around it and protect the rest of the horseshoe crab's body from toxins, and the same happens in the Atluden body.

This dual system emerged because of a defective gene that makes both individual system defective on their own (moreso the hemoglobine/mammal side of it). This means they have to partially work together to make up for the shortcomings. This allowes Atluden to survive in both air and water but needing both to properly oxygenate, although air is a lot less necessary than water, as they can and often do go for weeks without a breath of air, depending on the subspecies, with the deep-sea subspecies getting all the 'air' they need from sporadic underwater cave airpockets and oceanic vents.

Commensals
Atluden that are deeply bound to the water (and so dont venture much or at all in dry enviroments) often sport as a form of jewlery, living organism that can range from specifically bred crabs on the ears and tentacles, with duller claws to not hurt the host, to glowing bacterial formations spread on the face and body like makeup or bodypaint. In the case of more adventurous Atluden, the animal has either to be able to survive essiccation, or reside permanently in a wet area like the hair of the host, which tend to remain wet even after long periods.

Deambulation
Atluden do not have a singular tail like the sirens of the myths, but two well developed legs that can propel them at high speed in the water and even allow them to jump out of it akin to a dolphin (but not as high). They can also walk on land, with difficulty, by tying these long fins upward against their legs. Often soft and confortable straps, or spats, can be tied to the foot to keep the fold in place, while providing support and protection for the underside of the foot and especially for the folded fin, which is innervated. Its important to remember that while humans are used to have their feet callousing over, in the sea there is little use to walking and especially avoided in the sharp reef, so the foot of the Atluden is not as resilient.

Culture and Mind
The Atluden aren't folks of high emotions, both negative or positive, and not very inquititive or curious, compared to the other species of Kylorne. They deal more in 'black and white' or in practical terms than phylosophical (with rare exceptions of course). They deeply respect traditions, and seldom question them. That said, there is little to question, as the culture has settled in one of honesty and respect, and traditions are meek and unintrusive.

Their homeland is remote and unknown, hidden from the outer world, and shielded from cultural contamination. Despite this, there seem to be a common ancestor with the cultures of the outer world, and some hypothesize the Atluden to be the 'living fossils' of cultures.

Curiosity
This low aptitude for curiosity and exploration is episodically dotted with slightly more curious individuals, once in a very long while, a century or two, which then go on and explore a bit further than the Atluden that come before, sometimes creating new settlements, or reclaiming abandoned ruins (more common), tho even these exceptional individuals still have a lower amount of curiosity compared to humans.

If the lack of curiosity is a naturally occurring genetical trait or an artificially created one, it is unknown, but the effects of going against it are chronic and escalating.

Even a 'more curious than average' Atluden, if pushed by necessity to sport curiosity and 'go look in the dark', he or she will start to feel physical effects of the cognitive dissonance, ranging from headaches, nerve pain, general inflammation and, if the cognitive dissonance is experienced for very long periods of time, even autoimmune degradation. The symptoms will start very slowly to appear, sometimes taking a while for the individual to notice, and will keep getting worse the more the 'curiosity' is sustained.

This doesnt seem to apply as much, if at all, to investigating for reasons other than curiosity, like the case of searching for an intruder, investigation to the end of law-enforcement, and immediate problem solving.

Religion
Its unusual for an Atluden to have a different religion than Tidalism, in which case agnosticism and atheism is usually preferred to an outright different religion. The Rulers (Tlatoani) of the Atluden are usually also the head of the religion.

Stone
The Atluden seem to have a special regard for smooth stone, not only in architecture, but seemignly in a more spiritual level, as if the stone itself was alive. This interest is not explained in their religion, and it seems to be the only case of departure from logic and reason of the Atluden culture.

The Event
Although the ruins of the ancients show the Atluden used to have an extremely advanced civilization and technology (which would now be considered almost like magic), the state of such structures tells a story of something cathastrophic happening, a cataclism of their own creation, a direct consequence of this technology, probably mixed with hubris and arrogance. Because of this event, the species was forever changed in both its biology/psychology (the lack of curiosity) and their access to knowledge and technology, thrusting them back to even before the middle ages, to a primitive state. This "Event" culturally scarred the Atluden to such a point as to make the Atluden regard any artifact of that era as (literally and metaphorically) radioactive, with stigma deeply attached to even just the knowledge that comes with it. The elders of the tribes are the ones that hold the majority of the knowledge on such topics, sharing cautionary tales to the youngens so that they too grow up to revere and fear the entirety of the topic.

Ingenuity
Even with the most important parts of technological advancements gone, and even with curiosity dampened, the Atluden still manage to find ingenious ways to navigate day to day problems, by using the 'natural technology' of their own enviroment.

For example, they dont have sheep in the depths, but it is possible to gather the excretions (Bisso) of seashelled creatures like clams to create fine clothing: this material is used by the animal to stick to rocks, and it hardens like cement, but treated in a specific way, it can become strand-like and be woven. They also dont have strong glue (weak clue can be done with fish), but there are some animals that construct their 'shells' by glueing together small pebbles and sand around them. This substance can be more easely used than the clam one, as the animal is an anellid (Sandcastle Worm), but it works basically the same, creating a strong but resilient bond.

Dry Spaces
Although Atluden prefer to stick to a wet enviroment, they are fundamentally amphibious, and so benefit from dry spaces. Just like a Human kitchen has a faucet and a sink, a model kitchen of an Atluden also has a source of air, often imported from outside of it (like an oldschool kitchen before the advent of plumbing in the human world), or even better, from a gas pocket within the kitchen itself, which gets plugged so to not let the air escape.

Just like water falls in air, air floats up in water, and this mechanism is taken into account when collecting the air, with big buoyant baskets or bells held on top of the 'faucets' of the air pockets to collect the air floating up. These air bubbles get used in 'dry rooms' (or in the bells themselves) where mixing of dry ingredients needs to occur. This allowes Atluden that are permanently bound to water to perform 'dry labour' like drying kelp, that when is then covered in oils as dry, becomes hydrophobic, allowing similarly hydrophobic inks to be used to write.

Another use of 'dry rooms' is in the medical field, where blood in the water would make a cloud, making visibility almost null, or when there is an infection of the skin, where water would worsen it. Although it is told that Atluden knowledge of medicine was once much more advanced, nowadays the available knowledge is sparse and almost primitive, with surgeries at a medieval level, and strictly performed by the elders.

Architecture
Atluden architecture is quite cohesive, in line with sticking to traditions, and features smooth stone buildings with a round or square base, with enormous carved murals and domed rooves. This for the more permanent and important buildings. Prismarine stone is used as accents and is more prevalent on the more presigious buildings, like temples. Very often artificial structures integrate directly coral, or have coral growing on top of them. For more temporary or leisure related shelters, they prefer ones made of textiles and wooden poles, mainly tents and awnings.