Here we have the full story of The White People by Arthur Machen, a very strange, dreamlike story indeed. There are lots of Arthurian images in this (the nymphs of the well) as well as pure folk horror — rural communities with surviving paganism, secrets beyond secrets. It feels as if it were channelled to Machen, to be honest, and has that flowing, dreamy quality.
Jung would have a lot to say about this story!
And Machen manages to make it very unnerving, as if you are about to stumble into a secret that turns your world upside down.
Of course, Machen was a ceremonial magician — a member of the Golden Dawn—
and you can see hints of ceremonial magic in the rituals the people carry out.