Elves

Elves are a strange case, they have been here since Borohiem was created, but back then they were just primates, small creatures lesser than humans, but as they got more intelligent the more they interacted with humans. You see, Elves are spirits, Mystic-type spirits to be specific, and spirits can adapt quickly to their surroundings, especially Elves. So when humans came around with their advanced ways, they started copying them, and eventually, they went from knuckle-walking hairless grey primates to something a bit more human than that. All elves are born the same, down to every hair, the only thing that differs from elf to elf is their interests. Once they are an adult this interest will make them who they truly are.
Elves can bond to things, literally anything, human, animal, object, or even an Ideal like peace.
Once they do their body goes through great changes, their hair and skin change color, their height changes, and they become their true self. Elves can switch what they're attached to, but every time they do it gets more and more painful.

Elves are one of the only kinds of spirits that can be human, most of them live amongst us, and they're just as bad as any other human; but a lot of people are concerned, what if this is all just a disguise? What if they're all tricking us? They are Mystic spirits, that's what they're known for. Because of this concern, Elves aren't treated very kindly in most places, the only place they're treated well is Miewyin, which also happens to be the province with the largest elf population.
Places like Jagertai don't even allow elves to enter the province.
Due to all this, a lot of elves lie low and try to cause as little trouble as they can, hoping that someday people will realize they don't mean any harm.