discuss the war

I think you need to narrow down what you mean by war. World war two is a very broad subject. I might consider what specific themes of the war that The Book Thief Deals with.

The dehumanization of the Jews was an early stage of the Holocaust. Hitler vilified the Jews, progressively stripped them of their civil rights, and ultimately denied that they were even human -- thus were the Nazis able to try to exterminate the entire Jewish race. Max bitterly remarks that, as a Jew in Nazi Germany, a cold basement is the only place he deserves as he hides from persecution. In Max's fantasies of fighting Hitler, he imagines Hitler propagandizing against him, condemning Max personally as a villain and extreme threat to the German people. The pervasiveness of anti-Semitic Nazi propaganda and the fact that Max is reduced to hiding in his birth country weigh heavily on Max's conscious, and he appears to resign himself to the notion of his own inferiority. Death's cynical narration echoes this sentiment. Max's self-deprecation is probably tied into his feelings of guilt over having left his family to save himself.

Of Hans giving an old Jew being sent to a concentration camp a piece of bread, Death narrates: "If nothing else, the old man would die like a human. Or at least with the thought that he was a human. Me? I'm not so sure if that's such a good thing." Death struggles to understand humanity's capacity for both good and evil. Death is stunned both by the murderous Nazis and mankind's irrational taste for war and by the few human beings who exhibit remarkable compassion and strength, like Hans and Liesel. Wondering if the human race is worth anything, Death is torn by this opposition and cannot reconcile it: "I am constantly overestimating and underestimating the human race -- that rarely do I ever simply estimate it." Ultimately, Death tells Liesel in the last line of the novel, "I am haunted by humans." It is the capacity of human beings to make different moral choices and the apparent capriciousness of these decisions that haunts Death, which is only capable of a single action.