Also, I think the author oversteered because the last work is harem and sex all the way to the bloody end. This current one has no oyster to slurp on.
Nah. The mother was his main motivation for the first 200 chapters with him taking care of her. Then somewhere somehow, after sending the mother elsewhere, we no longer acknowledge her existence.
And that answers that. The thing is, a lot of these problems come from a lack of proper structure. You see these cracks widen the longer a story is. It takes a certain dedication to write a long story and maintaining its flow and weight. I will say from experience, doing about 600 parts or so. The amount of information is extremely difficult to manage.
It took a lot to keep things in line, while introducing fresh, and better ideas without losing the core. One way I had done this, was when I knew things couldn’t continue without losing quality. I came up with Book 5, 6, 7 as standalones while also extensions of the main story.
Book 8, specifically was more for a break book with interesting ideas and concepts with its own small end. Book 9 as the conclusion. For that last book, it went full into its core one last time. Character stories that link the core, six antagonist story parts that covers them, and further connects things.
One break story, which also shows something subtle but important. Then an incredibly strong finale to finish. With Part 7.5, 7.6, 7.7, 7.8 specifically covering the protagonists from Book 5, 6, 7, concluding their story. Which links into the end point. Part 8, 9, conclusion. This entire thing showed once more heart of the series before it concluded.
What I am saying is, the longer a story. The harder it is to keep the same quality going. Many fall off after the 100 point. To clarify, 7.5, was Book 5. 7.6, Book 6, 7.7, Book 7, 7.8 Book 7. The protagonist from Book 7 had it insanely rough. But these are things I had to consider.