Board Thread:Speculation House/@comment-4047010-20160206215454/@comment-410526-20160216105946

I think she's some kind of ancient goddess/demon/witch who existed before humanity (or at least before human civilization). The Grimm are her creations, sort of similar to the Schnee family summoning Semblance, but far more powerful. So she's not a Grimm herself, but they're closely linked in that she controls them and they owe their existence to her. At least that's my current theory.