Mmhm! Legendary beasts, things like that. Our world's "supernatural" can be divided into four categories. [Holding up one hand to count off as he works at this WEED.]

Things that come from living humans, things that come from dead humans, things that come from living non-humans, and things that come from dead non-humans. A yao would come from a living non-human, for example! And a ghost would come from a dead human.