Assuming that this manga is first serialized in a magazine (as most mangas do) before being put together as a book of its own, during the magazine serialization the editor and the magazine actually do have quite a power over the author (actually the magazine owns the license of the story, not the author themselves, so if a magazine goes bankrupt while a manga is in between serialization the author can only continue it if they bought the license back)
So it could be that the magazine sees the original approach to not be popular, and suggest the author to change style. Authors might disagree but, well, eventually influenced to do so. It’s not always the author that gets to decide how the story will proceed.
*usually manga magazines is a collection of different ongoing manga (just the latest chapter though). For chapter after ch1, you sometimes see tiny box of text summarizing what happened in previous chapters. If readers haven’t been following the story before, it could actually be easy to take a whiplash turn from how the story was previously. Just that it’ll be much more obvious when the manga chapters are collected in a book later...
Yea I get it and I feel bad for authors in that situation, but it’s something that I have seen pretty consistently through multiple manga and manhwa. In the long run it just seems obvious to keep it consistent but since most of these companies are banking on the periodical success it’s understandable why they would force the authors to change the story.
It started so strong and then the author just decided to drastically change the tone of the story in the middle of it. Like one minute it’s a gripping physiological and the next she just decided that she actually wanted to write a fluff. But she just didn’t feel like changing the first part of the story and all we’re left with is this.
I can not stress this enough; if you are writing a story and choose a general tone STICK WITH IT. there is absolutely no way to change a dark psychological into a fluff if you don’t set that shit up from the beginning.