So she was...
Possessed by some kind of malevolent demon? Was she the ghost of Glenda's mother?
The woman guest (Mair) mentioned something about how "she would need a body when she returned" and she was frightened that the area called "the rise" was disturbed. That sounded like a local legend or something.
I wanted to like this, and I'm not saying I didn't. But I'm trying to make sense of it. What happened here? She brought out some madness in these people, and destroyed them all. Why?