Just the main story of Honkai: Star Rail. I didn't pay much attention to the story while playing, and I'm too lazy to read it on my own. It felt like a prison sentence, so think of this as listening to the story and experiencing it all over again.
In the future, Stelle becomes a true Aeon of Trailblaze. But becoming an Aeon means losing her humanity. To reclaim it, she returns to the past and observes her former self, anchoring her humanity once more.
To avoid affecting her past self, she has no choice but to become Caelus and cause trouble. So Caelus did all that. What does any of it have to do with me, Stelle?
In your book, the protagonist has no sense of involvement and is more like a movie-watching novel.
The protagonist's name doesn't even appear a few times, it's just a copy of the plot [awkward laugh]