I'm a librarian who loves anime, manga, and reading a wide variety of genres.
I'm not quite sure what I'm listening to. Something happened to Constance and Mary Katherine's parents a few years ago, and it's left Mary Katherine with a deep "I wish you all dead" rage against the townspeople. They really do seem to dislike her and the rest of her family, but no reason has been given yet. And Mary Katherine and Constance's sole visitor just implied that, whatever it was that happened, Constance has been feeling responsible for it. I'm wondering if Mary Katherine had something to do with whatever happened, though. There have been multiple references to her not being allowed to handle food, or tea. But she's allowed to pour milk. If I take that at face value, it's possible that Constance is overly controlling, or that her anxiety extends to food and drink. Or, hey, maybe Mary Katherine poisoned their parents and all this "don't touch the food and tea" stuff is just a precaution.