Animorphs rocked my world as a kid. It was a scifi series marketed to children but dealt with really dark topics. The lighter topics were what is family when stuff like divorce and aliens replacing your family members. Then some of the books delved into serious moral questions like, what does it mean to spare a life if that person is at risk of betraying you and your team, to should we drag an unrelated species into our war even if it’s against their values. The whole overall plot follows child soldiers who were unwittingly drafted into a intergalactic war that they cannot tell anyone else about and the trauma that brings about. The series surprisingly didn’t try and lighten the weight of the moral choices presented too much. While the protagonists were always “in the right”, they were constantly forced to cope with the consequences of their choices.