>>22361142It's never really elaborated on, but I think it'd a pretty safe assumption it works the same way Marvel explains having Norse gods in their world.
They aren't gods, but in the past when people encountered them, they had such immense power the people assumed they must be gods.
>>22361189Not all of the legendarily are one of a kind, and that's canon. I forget which ones, but I'm pretty sure the legendary birds are canonically not one of a kind. There's a picture explaining this if anyone has it
