I’m starting oddly enough with the end, as that’s what I got asked most about. I got asked about how they die and if Guren resurrects them. I’ll make another post or two about different sections I got asked about. Obviously there are major spoilers ahead. Also, take my translations with a grain of salt as they are paraphrased and may be out of context.
Main points: Mahiru is the one that kills them, she dies by Noya’s curse, her plan was to disrupt the ultimate experiment by having Guren there, he decides to resurrect them, and the book ends there, as the world’s destruction begins.