Decided to make a little introductory post to a very particular crossover AU (for ABZU, The Pathless, Journey (2012), and Sky: Children of the Light, to be specific) that @abhorrenttheorizer and I have made art for over on Discord. As there's a lot of ground to cover, I'm putting it under a read-more for courtesy.
Introduction
Welcome to Earth! Specifically, thousands if not millions of years in the future, after at least one cataclysm has claimed the lives of every human on the planet. But not to worry!
A little before the end of humanity arrived, two bird-like gods arrived on Earth, settling in the eastern and western hemispheres to establish their own followings.
Off to the East, we have the goddess affectionately nicknamed "Megabird," who landed on a mountain and began constructing her own unique ecosystem centering on light and flight, creating the Rythulians as her worshippers. (AT's more in charge of this portion; he's got a lot of interesting ideas about the "slugbirbs" as we like to call them.)
To the West, we have the goddess known to her own people as Mother Eagle. First, she got to work producing five eggs, which would hatch into their own unique gods and goddesses: Cernos, Sauro, Nimue, Basilla, and Kumo.
Basilla, the shark goddess*, was the one who crafted the people who would become their worshippers, taking remnants of humans and mixing them with seals and sharks to create the Basillan species (my specialty, based on my personal headcanons for the TGS games).
*(based on the Great White from ABZU being referenced in The Pathless and the mysterious stele that got edited out in an update)
The original Basillan kinda looked like this (these being the "humanoid" forms of the Tall Ones, Basilla included).
However, they wouldn't stay united for very long. Differences in religious views and lifestyle got heated, and eventually the mortals banished Basilla and her followers from their island home, with the Basillan cult setting up shop in an underwater territory a ways away from the Eagle's Island. Over time, the more land-focused followers of the Mother Eagle and the remaining four Tall Ones became the Vokara subspecies, and the more aquatic followers of Basilla alone became the Nanshen.
Here's a really old drawing of the differences!
(Did I forget to mention this AU has been in the works since 2021? Man my art's changed since then.)
Anyways, average Nanshen guy on the left, average Vokara guy on the right.
The Nanshen are more suited towards an aquatic lifestyle, with wider gill slits, darker skin due to heightened sun exposure, shorter and more compact body type, a flatter nose more suited for passing water to the gills, and longer barbels on the ears to allow for greater olfactory sensation underwater. (They're based off of the murals in the ABZU game, as well as probably unintentional environmental storytelling with how unnavigable the map would be without a lot of diving underwater; it only made sense to me that the lost civilization was probably amphibious.)
The Vokara have lived mostly in the mountains for generations, so they're more suited for terrestrial life, with a broader chest, smaller gills to focus on breathing air, lighter skin due to weather conditions providing less light, a more opened up nasal passage for ease of breathing, and smaller barbels due to less of a need for underwater sensory measures. (They're more based on the Hunter's appearance in The Pathless, given that she is way too gray to be a human. I know it's probably just to make her aracial like what they did in Homestuck, but I'm running with it damn it!)
(Anyways, here's a nicer comparison drawing from a little while later. Behold the specbio lesbian wedding!)
Fun Bits I Forgot to Organize
Tusks
Adult Basillans grow tusks like boars (based on the Godslayer's ascended model having these wicked tusks among his rows of fangs). They only really develop towards the latter portion of adolescence, around one's late teens to early 20s, and are regarded for the males as the sign that one has become a proper adult.
Of course, the downside is that these things are continuously growing and have to be trimmed every now and then in order to avoid poking oneself in the eye or scratching people with it.
The Vokara are especially finicky about covering their mouths for... not quite modesty reasons so much as baring one's scary teeth at another person is considered rude and aggressive. The Nanshen, living far more amphibiously and thus not really comfortable with more cloth than is comfortable underwater, don't care about that as much, though if you grimace at somebody they might kick you in the shins.
Barbels
A general rule I keep when designing out-of-water clothing for these guys is to cover the ears. In universe, it's because their barbels are very sensitive to differences in temperature and UV radiation out of the water, so it's deeply uncomfortable to have them uncovered for these guys. Out of universe, it's because The Hunter did something like this in her game, in addition to the ABZU people also covering most of their heads but not their chests for some reason (so probably not quite a modesty thing), and I decided to make up a silly specbio reason for it.
For some examples, here's a spread of different Nanshen city states and their different fashions:
History
The games are still canon here! But there's a little more to it.
The Nanshen had always been travellers, more keen to explore and establish their own territories far and wide. But after those dwelling in the Crown began messing with the Abzu, the life energy of the ocean itself, the ecosystem around the capitol collapsed and the population fled the area. Their former empire collapsed, and in its place, a number of different city states off the shore of their various old territories were established in its place.
Some time before, or maybe simultaneous to that, the Vokara had their own little collapse in the form of the Godslayer's rebellion. Many had read the writing on the wall and fled the Isle before he successfully slayed the gods and took control of the whole Island, leading to a number of villages and kingdoms being formed on the nearby continent, which would eventually spawn the Last Hunter, who would defeat the Godslayer.
There's more to it, but I think I'm approaching Tumblr's picture limit, and I've got more, sillier pictures from the AU. I'll add those later!