User blog comment:Withersoul/How would man have fought against the grim before using dust?/@comment-10390252-20130902144144/@comment-23784953-20130902151309

I... wouldn't say it was that quick. Though Great-great-grandpa Arc faught in a war, it was never really confirmed he faught in the Grimm Wars. Theoretically, I'd say the Grimm War took place at least a few thousand years ago and went for at least a few centuries, before Dust started turning the tide in favor of humanity.