Adaptation generally works on need to not need situations, in cold and cloudy weather you will have paler skin to survive the cold, in warm and sunny weather you will have darker skin so your skin wont burn so easily and withstand the heat better, and in extreme weather you will have stronger bodies so they can last longer and survive better, like the Ohmish.
To need better hearing would mean that you live in an environment where NOT hearing better would mean your death: like forests, jungles, or anywhere that is heavily populated by predators.
forests would also makes sense, since the Proto Elves would need better balance to climb trees to avoid predators or find food.
The early Humans probably moved to to more flat lands where you generally see what's coming like the plains, meadows or desserts, so they didn't need better hearing. Maybe the early Humans developed better eyesight to compensate for a lack of better hearing, or denser bones to make up for a lack of better balance.
I say this because it doesn't make sense for Elves to be just better then humans without compensating for anything in terms of biology.
I cant really say much about Novencia since there isn't really a lot of lore I've seen to theorize about, except for the demon cults.
Although that
could explain the Dark Elves, long term exposure to demons and demon magic could have turned their Elven ancestors skin dark, eyes red and hair to a silver white. So maybe the more you get away from central Novencia, the more varied Dark Elves become.
I find the Suaria
very interesting.
Since they are cold blooded, them living in cold environs could spell a lot of health problems for them, from getting sick to straight up DYING. So I wonder how Hiho plans to deal with that when she gets to Ohms, I can only imagine her wearing a giant sock on her tail to stay warm lol.
This is the first time I've heard of the "Sultanate" so ill take your word for it. Though lets be honest, if a military nation says they are autonomous, you don't have a choice in the matter. You either agree or you get invaded.
Anyways, it would be great to get more background into Redics life, cause if I'm guessing correctly, I don't think the red vagrants were bandits. Besides, I love the story updates, the last one spoiled me

.
Now demons and demon magic...
To start, I don't think you can classify them as a race, a species or even as proper living beings. Demons are like a force of nature, coming into the world out of nowhere and existing suddenly and then becoming anything; A rock, a tree, an immortal anomaly of geometric shapes that would probably outlast the entire universe.
They essentially ARE demon magic, born from it and molded by it, for them using it is like breathing.
That's why I think the term "essence magic" is inaccurate, because it not really magic. Its an entirely different plane of existence, trying to draw power from that would be like attaching a battery(person) to a lightning rod and hoping when lightning(demon magic) strikes the battery wont
explode. Asking demons to teach you also feels pointless, because its like a fish trying to teach a person how to be a fish. You either drown trying, or you're flopping in a lake, looking like an idiot.
Ultimately I find demons to be truly alien, something from another plane of existence that no one truly understand, maybe not even demons themselves. Like the warp from Warhammer 40K.
As for the Zahra and Ohmish demon magic users, I would ask what the general mortality rate is, cause I'm guessing it might be high...
(Did it! man, this one took a while!)