@kleiner
Woah there, man.
I'm pretty sure that's a spoiler from the last arc of the story, and many answers were tied to its reveal. At least in the WN
@cache_bag Evidently, not enough artists/assistants. While writing this a conspiracy theory came to my mind -- maybe manga publishers figured out that it's easier to extract more money over a longer period of time. I.e. readers cumulatively prepared to pay more in less frequent portions. Something like that.
The MC makes the strongest rock bullet he possibly can because the demon is known for his hardness, and he blows off the entire top half of the demon's torso. He then recovers (I don't remember how though).