In some footage of one of his notorious on-set flare-ups, Klaus Kinski yells at Werner Herzog that he's "a dwarf director!" This apparently random insult is a specific reference to Herzog's movie Even Dwarfs Started Small (1970).
During Klaus Kinski's infamous temper tantrum on the set of Fitzcarraldo (1982), which he mostly aimed at production manager Walter Saxer, he yells that he "isn't sitting in that fucking costume in his fucking car in Holland this time." He was referring to the production of Nosferatu the Vampyre (1979), which was filmed in Delft, a city in South Holland, Netherlands, during a hot summer. Kinski was driven to the set in full Nosferatu costume and make-up, in a heated car, which irritated him greatly.
Werner Herzog says in this movie that Kinski wanted to leave the set because he was upset about something and Herzog threatened to kill him with a rifle if he did. Walter Saxer, the executive producer, said in an interview in 2012 that this story was totally fabricated, like most of Herzog's narration. He said Kinski was the only one who had a rifle at that time and that Herzog used Kinski's legend to bolster his own. Interestingly, Kinski relayed in an interview with David Letterman in 1983 that Herzog had threatened to shoot him but didn't have access to a rifle.
The film details the long and often complicated relationship between Werner Herzog and Klaus Kinski. The film also the last collaboration between Herzog and his friend since school, Florian Fricke of Popul Vuh. Ficke composed the score of many of Herzog's most famous films and passed away in 2001. On the liner notes to the Nosferatu soundtrack, Herzog calls Fricke the "angel on his shoulder to Kinski's devil."
Werner Herzog claimed that he once considered setting Klaus Kinski's house on fire, because he felt genuinely intimidated by the actor. Fortunately, before he was able to do so, he was disturbed by Kinski's shepherd dog.