Board Thread:Speculation House/@comment-4830106-20131108040231/@comment-7607511-20140211192940

I like to think of the Grimm as the manifestation of the pure unadulturated evil or rather malevolence nature has for mankind. Maybe she doesn't want humanity to rise up from the primordial ooze and build civilizations. So she sends her dark, souless, timeless hordes of natural human killing predators to keep humanity in check.

Another way I enterpret the Grimm is that or every soul a human posses, a Grimm has to exist in order to counter balence it. And the more powerful the soul or aura attached with it, the stronger the Grimm will be to counter it.

Or they could just go with there being a big Grand Master Ancient One type Grimm who's in control of the lesser Grimm and who also just happens to have it in for humans in general.