if you aren't asking yourself the question “why is this story being told” throughout the entire process of putting together your folktale you are failing; it's not as simple as coming up with a cool story and sticking a folkloric wrapper on it
folktales can be cool stories!! but they're never JUST that; they're always informed by the agendas of the people telling the tale
the dude over here giving an entire theogony just to tell a story about a yokai