This is where the settings' power-levels come into question.
We saw that the MC managed to take down a house-sized creature with a bomb (albeit it is not clear how she managed to cleave off such a sizable chunk of meat, from the creature's head from that one thrust...)
And now, we see that a veteran hunter is able to take down a building-sized creature. Its head is not blown clear off, so it's implied that he took it down with just his tools.
I can obviously continue reading and see what's what, but from this chapter alone -- it makes ye scratch yer head and go: "wait, how?"
I hope the veteran used some form of advanced explosives, poisons, or some form of core-detection technology, or the remarkable instinct / skill to detect where those cores are, and dig em out' himself.
Otherwise, if that old guy has a """power""" that allows him to just take down a building, it'd be pretty darn odd, considering the setting seems to establish that everyone are semi-regular human beings, with all the limitations that come with that. This ain't Dragon Ball, is what I'm saying.
Anyway, I'll just keep reading. This shit is dope.