User blog comment:Zathronas/Analysis by an author: World of Remnant, Grimm/@comment-10390252-20141017104932/@comment-10390252-20141017131918

No, that Grimm was made to destroy intelligent life-forms and their artifacts in a planeatry environment. There is no complelling reason to believe that humans were specifically the target, especially given the time-frame in question (possibly tens of or even hundreds of thousands of years to before the earliest written history).

1) The behaviour and nature of Grimm does not in any way support any suggestion that they are part of Remnant's natural ecosystem. If they did not evolve, then they were created. Whether on a drawing board, a CAD program or in a necromancer's study is merely semantic wrangling;

2) The prologue narration of volume 1 strongly implies that Grimm emerged after man's rise. This proves that Grimm are a reactive force and likely did not exist at all before their prey. This and their behaviour strongly suspects that tis artificial creature is intended only to fight and destroy intelligent life-forms; no intelligent life-forms and they are dormant.

Who created them? I'm not sure that matters; who and whatever they are, they're probably long gone.

Well, have you ever read the story of Star Wars - Knights of the Old Republic? In that, the protagonist found an automated weapons factory in deep space called the 'Star Forge'. It had been created by a long-extinct civilisation to mass-produce weapons to use against their enemies. I'm wonderin if, maybe in several places on Remnant, there are Grimm Forges that, now their systems have detected intelligent life, are mass-producing Grimm to fight them. The fact that humans are not the species that the Forges were created to annihlate is meaningless; to their decaying AIs, all that matters is humans and faunus vaguely match their target criteria and thus must be exterminated.