This feels like an extended Oneshot. Spoilers ahead:
After reading all 6 chapters, I'm still unclear why they're hunting these demons. They all seem to be unaware that they're not human, even once they turn into their demon form they seem to keep their sanity too. That security guard guy actually saved Sasa's life despite her trying to kill him, and she didn't give a fuck, just kills him anyway.
I don't get what the whole classmate thing was about, they show one of the girls having sex seemingly just to have a sex scene that lasts all of one page without even showing nudity, what the hell? None of that connected to the main story, it just seemed like a waste of space distracting from Sasa's hunting.
They introduced FOUR new characters in the final chapter, what the hell? Weird smiley guy at the office who suddenly hints he's a genocidal maniac. Demon kid wearing a blindfold. Half-naked long haired guy who leads a dozen demons. Then a freaking time skip and a new girl character who says nothing, and it just ENDS.
I hear there's a sequel, but...why? This doesn't stand on its own legs in the first place. Shouldn't the first part be self-encapsulated and interesting enough, instead of relying on a sequel coming out?