{If we’re talking about the one where people and pokémon were once the same species (or at least married each other), the latter, I have to admit: it’s just a myth, not really truth. It’s more or less the equivalent of all those Greek/Roman myths about Zeus or Poseidon or somesuch turning into swans or bulls to go after mortals, except somewhat less … disgusting.
To go just a tiny bit more in-depth, the thing about that myth is that it’s (seen by modern anthropologists as) an attempt from early/prehistoric humans to “humanize” those strange, magic creatures with whom they shared a world. That is, in order to fully understand aspects of their world/pokémon themselves, the people of the pokémon world would write these elaborate tales that featured pokémon that essentially lived their lives as humans, that talked and plotted like humans, or that were literally humans at one point or another but were either transformed into pokémon or could go back and forth between human and pokémon forms at will. Somehow, some of the origin myths (or in other words, prologues to such stories) wound up in books about the origin of the world itself, which is why some people might be confused or might otherwise think humans and pokémon are related.
It doesn’t help that a number of humans do actually display the abilities of pokémon (psychics, Aura users) or some sort of affinity with pokémon (anyone who can talk to pokémon, such as N), but as far as anyone knows, these abilities are unrelated to pokémon … despite the fact that they’re still not well-understood on their own.}
