Oh--artificial, you know? Made from chemicals.

[ It hadn't occurred to her that Zenitsu wouldn't know that! But then, if he's from the same time as Tanjiro, maybe the concepts are sort of new for him. ]

I don't know if there was nothing before, but real paper is definitely pretty rare around here. There are hardly any trees here, right? And the natives probably haven't thought about using it for a long time. But I guess with us here now, there's a demand for it.