>>211506240There's that, and also right now I'm reading the Star Wars Jedi Apprentice series and that also rules. I think it was common for YA authors to consciously add very adult themes and concepts into books aimed at younger teenagers while being fairly safe in the language to slide past the censors.
K.A. Applegate specifically intended to show the effects of war and paranoia on a bunch of child soldiers. Which really helps make the stories feel so much bigger. Like that one moment in one of the earlier books where the kids want to sneak into someone's house and think they can do it by turning into ants and going through an existing tunnel, but things go quickly and horrifically wrong because the colony living in the tunnel see them as outsiders and a threat so start ripping them apart limb from limb. Great stuff. I really need to finish the series.