They are pre-humans evolving from butterflies, who in their times of struggle had to form mouths to be able to feed off the blood of other animals to be predators. No one knows for sure how they ended up this way, folktales said that it was a butterfly that first made a wish. This is why the Lepidopterans and the celestials in the sky have a close relationship due to their ability to communicate.

Of course, time is linear and the world and the creatures in it change.

Eventually Lepidopterans became self sustaining to be the new humans in this dream world.