The core of the essay-worthy material here is how much misery can be avoided with clear communication. Lieselotte’s tragedy in the original game was caused by her inability to express vulnerability.
Rather than making the villainess "good" by changing her personality, the story redeems her by helping others understand her. She remains her proud, stiff self, but she is finally loved for it.
Endo and Kobayashi explain her true feelings to Siegwald in real-time. This creates a hilarious and sweet dynamic where the Prince begins to see her "sharp tongue" as a sign of deep affection. Key Themes