Last Reasoning of Kings

During Frank's WWI flashback in the desert, just before he turns over the dead German soldier, clearly shown on the back of the soldier's helmet is a Nazi eagle and swastika. Neither of these were in use by Germany during WWI. The version of the swastika that was eventually used in Germany was designed by Hitler in 1920 and was not used as a national symbol until 1935. Furthermore, insignia were not painted on the back of German Army helmets.