User blog comment:TheLoneClone/The Cabin in the Woods Q&A & Discussion/@comment-29996529-20170701034158/@comment-4501923-20170702003036

Krr'Sa'Thu'Tin (or, for time's sake, let's call him the Demon) is, well, a demon from the Dark Dimension. I don't want to go into too much detail for the story's sake, but he is very important to other dimensions. He is very powerful and a force to be reckoned with.