Antagonist Protection Service

Sorry for my English, but I love reading so much that even a translator doesn't bother me. A wonderful immersion. I really felt the importance of the choice facing the hero. It's also so difficult to kill a person in cold blood. It's really good work in terms of immersion. However, this can also be a disadvantage. Sometimes the hero gets lost in his thoughts about unimportant things for several paragraphs. For example, in my opinion, the system was discussed for too long. But that's just my taste. Another thing that really made me abandon the work was the explanation of why the protagonists need to be killed. So, we were told that the protagonist sucks the stability out of the world and if he is not killed, the world will perish. This was said three times in different words. Three times we were told about lofty matters and not once about how it looks in practice. If the protagonist kills the antagonists, what will happen? Will tectonic plates shift, will a meteorite fall to Earth? Will some ancient evil awaken? In short, what will happen? How do the antagonists keep the world in balance? This explanation is sorely lacking. Now for the fundamental question: the library stores books about illusory worlds. Hypothetically, if you open a book, you can read a story, and in this story there are protagonists and antagonists. The protagonist is the character who plays the main role, the leading role, he is at the centre of the story. And that's why they have to be killed? Won't that destroy the foundation of the story? It's like killing Sherlock Holmes in ‘The Return of Sherlock Holmes’. So does that mean the library destroys its own stories? Or, from the point of view of the Illusory Library, the Illusory World will be the protagonist. So on the shelves there will be a book not about the hero as the protagonist with a story, but a book about the world with its history? In short, something is clearly wrong here.