To quote the book #5:
Tap for spoiler
”It’s going to get worse before it gets better. We are going to lose more friends. We’re going to have to do some pretty horrible things just to survive…”
Book 5 is just scratching the surface, but the tones get worse, not better, at 5 you should understand this about the story.
To say it’s not cruel, is so weird, and a few of the nonmain protagonists are gone, they don’t stay the same from book to book.
To quote Dinnamin
”if I don’t like their voice, I kill them off”.