There are many incredible stories of heroism in real-life, some in my own family. However, since you included the realm of fiction in your question my choice is Paul Bäumer, the main character of “All Quiet on the Western Front”.
Sharing Paul’s story as a German soldier during World War I enables civilians to understand, at least somewhat, not only how combat veterans think, but why. When the reader finally understands the meaning of the book’s title it should haunt them.
I firmly believe that if those in power actually read this book there’d be fewer wars.