One of the main themes is war and its brutalities. The novel shows the harsh realities of war, like destruction and loss. Another theme is power, both political and magical. Characters constantly strive for power, which drives much of the plot. And there's also the theme of identity, as the protagonist struggles to find her place in a world full of chaos and conflict.
One of the well - known American war novels is 'The Red Badge of Courage' by Stephen Crane. It vividly depicts the psychological state of a young soldier during the American Civil War. Another is 'For Whom the Bell Tolls' by Ernest Hemingway, which is set during the Spanish Civil War but also reflects on war in a broader sense, and has influenced American views on war and heroism. Also, 'Slaughterhouse - Five' by Kurt Vonnegut is a unique take on World War II, with its non - linear narrative and satirical look at the brutality and futility of war.
Rin is definitely one of the most memorable. She is the protagonist and her journey from a war orphan to a powerful figure is quite engaging. Another is Altan, with his complex personality and his role in Rin's life. He has a great influence on her growth and the events of the story.
One idea could be to combine the magic systems. In Naruto, there's chakra, and in The Poppy War, there's shamanism. Imagine a character who can use both, creating unique combat styles. For example, they could use chakra - enhanced shamanic spells.
Well, one key feature is its rich world - building. It creates a vivid and complex world full of different cultures and magic systems. Another is its strong characters who face moral dilemmas and grow throughout the story.
Since it started as fanfiction, it might have initially been classified in the same genre as the work it was fanning. But as it became its own story, it could have blurred genre boundaries. For example, if it was a fanfic of a fantasy work, it might have added elements from historical fiction or military fiction as it developed, making its genre classification more complex.