Is it just me, or does this feel like the final arc? I hope not, because I'm really enjoying this manga, but it really does feel like a final arc.
Yes, probably. Title drop (though isn't necessarily indicative, see witch watch), what is likely
the sealed monster being out, etc. I'd
like for it to go on a bit more, but the initial conflict of hero vs monster is over and unless Dethbiz is much bigger than just Dr. Toku, there's little else the author can do.
Either author had a short story they wanted to weave, or japanese people have zero taste and buy absolute dogshit like incel revenge fantasy adaptation #33 volume 18 instead and the rest of us suffer.