book 1. prisoners of war
book 2. shitty parents and child murder
book 3. the effects of an overbearing dictatorship
book 4. the ethical considerations in manslaughter
book 6. morality behind vengeance killings
book 7. abusive parents sacrifice a child to maintain their place in society
book 8. trauma of killing a lot of people as a child
book 9. a child murdering someone from book 2 comes full circle causing brother and sister to try to kill each other
book 10. harmful effects of intergenerational race wars
also theres the many attempts of genocide spread through the series and stuff such as torturing prisoners and a lot of killing