Board Thread:Speculation House/@comment-25051723-20140708033229/@comment-24757748-20140708034430

But the whole reason Dust was discovered in the first place was to fight the Grimm, who've been on Remnant longer than humans OR faunus. Unless the introduction was outright lying to us, there's no way for the creatures of Grimm to be a mere byproduct of Dust usage.