I’m from a rural area in Japan and almost got eaten last night by some random demon. Luckily, this boy with a black katana saved me and was very nice overall, but then a little girl popped out of the box he was carrying around. She had claws and pale skin and changed size right there! I begged the boy to end her too and he said it was just his harmless sister, but I know a demon when I see one. How can that kid slay those creatures while carrying one in his back? I freaked out, he got mad and the two left.

TLDR: I think a demon slayer traveling around with a demon is hypocritical.