Board Thread:Questions and Answers/@comment-24851346-20140503125209/@comment-162.40.231.167-20140503163910

Keeping in mind that the setting is more or less traditional high fantasy AND that the creator is Japanese(given that culture's generalized traditional stance on firearms of most any sort), I'd make an educated guess that it's medieval/Ren without the gunpowder. Hard to definitely lock that last bit, though. In any event, he certainly hasn't 'mentioned' gunpowder weapons.