WMG / The Blair Witch Project

The kids were being harassed by the Blair Witch Cult
Pretty much every single thing can be attributed to something not supernatural. The little twig figures, the stones, (mostly) everything was done by the remnants of the Blair Witch-worshipping cult commune that was disbanded in the 60s, mentioned by Josh in one of the movie's deleted scenes.
  • Change that "pretty much every single thing" to a solid "every single thing". The same thought occurred to me: why else would they have deleted such a brief and otherwise harmless scene, unless they thought that it gave away too much?
    • Um, then how did the Blair Witch Cult magically cause them to come across the same river twice?
    • They are really bad at outdoor survival and navigation. After all, they threw their map in a river.
    • You CAN change the flow of a river. It's something that you can't do in a minute, but with a lot of preparation, but you can do it. You can change some markings, scary some boys, and even use magnets to mess with someone compass. Keep in mind: The Cult has more sense that supernatual forces

The kids are being stalked by one of the Gentry from Changeling: The Lost
They inadvertently walk through a rather nondescript portal to the hedge early on in the film. The rest of the movie is the Keeper who owns the realm stalking them, planning to add them to it's collection. Reality warping is perfectly within a True Fae's powers, and it explains why they come across the same river twice. Josh is the only one who survives the movie ironically, becoming a changeling when he disappears, and then luring his friends to their deaths at the hands of the True Fae.
  • I had the exact same thought. Of course, I figured they all became changelings, though the film ended before it was shown.
  • Well knowing how they were and what they were after or being chased by...they probably got ripped into becoming Darklings; the dark-woodlands of perpetual darkness and spiky-trees sure do LOOK like the Hedge, Autumn Court Changlings for the WIN!!

The kids are being chased by Slendy
  • ...holy CRAP, that makes sense.
  • This is now my personal canon.
  • But the serial killer who took the kids' lives only stopped because a woman (the Blair Witch) appeared to him, commanding him to release the eighth (would-be) victim. Slendy has never appeared as a woman.
    • But several os his known proxies are women. He could've sent a proxy to speak for him.

The Blair Witch is the Demon.
Clearly, one of these kids has very naughty ancestors. Both the witch and the demon have similar motives and like to play with their prey. It eventually decides to stop dicking around, possess Josh, and then lure his friends to their deaths for an encore.

Josh killed his two friends at the end
When the witch claimed her previous victims in the past, she did it through the child murderer because she wasn't able to do it physically. And we know that Josh, who went missing, was in the house at the end because we heard him screaming. And it's implied that his friends are killed at the end, and we never actually saw Josh's body... ever. I'm not saying 100% that Josh killed his friends. But, if it did happened, I wouldn't be shocked.
  • I would; they found Josh's bloody clothes and some entrails in bundles of sticks. It's pretty clear that he died a horrible, gruesome, and from his screaming, a painful death.
    • The bloody things in clothes/twigs were just teeth. I'm sure the witch could "convince" whoever she was possessing to pull out some of his teeth.

Rustin Parr is still alive.
And he killed them. Why else would the climax take place in his house?
  • Jossed by the supplements as far as Parr's involvement; he was executed by the town not long after the murders, which he confessed to. The finale does happen in Parr's house though, but to add an extra layer of WTF, the house supposedly burned down decades before the movie takes place - the footage is found buried in the remains. Again, all this is mentioned in the supplements.

The Blair Witch unleashed a Candarian Demon.
Makes as much sense as anything else.
  • That's just fact as far as I'm concerned.

The Blair Witch was calling Josh a faggot.
  • Why else was his remains wrapped in a bundle of sticks?

The Blair Witch was a scapegoat.
Elly Kedward, the original "Blair Witch" who was killed during the 18th century, isn't behind the haunting. The forests around Burkittsville have been haunted or possessed since long before her death. Kedward was apparently killed after a strange new disease was already affecting children in the town, and was also apparently innocent. Along with a generally negative attitude toward the area among native tribes who lived in the region before the Blair settlement was ever founded, this would suggest that something odd was going on before Kedward's death. After she was killed, whatever lived in the forest used her story to frighten away most of the town's residents by convincing them that she haunted it. Its chief goal, and the reason why it allowed the film to be made, is to avoid human habitation that might threaten the forest's continued existence, likely because its survival is contingent on that of the woods.
  • Based on the motives behind actual witch hunts, your hypothesis is sound.