If this anime took place in Japan, 8 years after World War 1 ended, then why didn’t Demon Slayers use Fire Arms that shoots Nichirin iron bullets greased with wisteria oil to kill demons? Genya killed an Upper moon demon using a sawed off double barreled Winchester Model 1912 .

dead forgotten series.

>>281271308 (OP)
He did not, it's a fucking plot point that he did not. Also, the best way to kill demons it's using breath techniques you can't do with guns, Genya only uses firearms because he's absolutely incapable of doing proper breath techniques and he would be dead for even trying to fight demons with guns if it wasn't for his eating demons ability.

>>281271407
https://desuarchive.org/a/search/image/vWnSnRMc-TsrDMjU8-ASzg/