This film's ideas gain more relevance with recent events
This was several months ago, so pardon me for not bringing the connection here sooner, but I'm sure some of you might remember this:
http://www.jsonline.com/news/crime/waukesha-police-2-12-year-old-girls -plotted-for-months-to-kill-friend-b99282655z1-261534171.html
"Slender Man", much like this franchise's Blair Witch at the turn of the century, is another big success of what they call "fakelore". A meme created in a Something Awful forum in 2009 that's managed to gain remarkable traction to the point that this supernatural character is now everywhere. T-shirts, videogames, webseries, a feature film not far off in the distance.
So inevitably, this big cultural phenomenon has the side effect of some people who are utterly lost on the difference between what's a manufactured fantasy and what's reality - which, yes, is partially the point of "fakelore", the way it creates this fabricated narrative that sort of presents as genuine folklore. The idea at the center of Book of Shadows is to see what happens when that big cultural confusion over what it is and is not real is shrinked to this microcosmic level, between these increasingly unstable characters. The results, of course, are ugly.
This doesn't mean that the morbid content of some of this homegrown mythology (be it that of the Blair Witch or Slender Man) is somehow responsible for violent acts in real life. That's just ridiculous scapegoating. Still, I bring it up because it's a very interesting parallel to the events of Book of Shadows (and the culture that these events exist within).
The bitter thinkers buy their tickets to go find God like a piggy in a fair