There are some interesting theories out there, with some of the best ones being angel or alien possession. I could see merit in either/or, honestly.

I enjoyed how they revealed the reason for the cult-ish sacrifices in the woods. That was a huge question mark the whole season (especially Lenny's behavior) so I'm glad it was explained so organically. It's interesting to see complicit behavior from "regular" humans when they see possession (FUCKING POSSESSION) in their loved ones.

Damn good show, hopefully it picks up viewers from word of mouth though.