Quiz

During filming, director Harry Kümel hit actress Danielle Ouimet during a dispute. Actor John Karlen was so infuriated by this behavior that he punched Kumel in the face. The atmosphere on the set was understandably tense afterwards.

Shot entirely in English, even though the majority of the cast was French, German and Flemish. As opposed to most European "genre" films from the 70s, here none of the actors were post-dubbed by others. They can all be heard with their own voices (resulting in some accents), notably Delphine Seyrig's deep, smoky voice or Andrea Rau's and Paul Esser's German accents. Seyrig and Danielle Ouimet reprised their roles for the French-language dub created for the film's Canadian release, while Rau dubbed herself in the German version.

In 2007, Harry Kümel revealed in an Interview that initially, Delphine Seyrig, already being a well-renowned icon of sophisticated European cinema, wasn't too eager to take the part of the Countess Bathory when he sent her the script. Seyrig's Boyfriend, famous French Director Alain Resnais, was a big fan of graphic novels and when he imagined Kümel's material and idea of the film to be something of a graphic novel, he enthusiastically convinced Seyrig to take the offer. Kümel also said that, at that time, he and his co-writers thought Seyrig's consent was "too good to be true".

Harry Kümel's original choice for the role of Stefan was Malcolm McDowell, who turned down the part. John Karlen was cast at the behest of the film's American investors, and Kümel was disappointed with their selection because he felt that Karlen was notably older than in the headshots he had been given of the actor.

The U.S. version has lyrics over the opening theme: "Whispering through the night, Wings.......wings....... Silently sliced the darkness, Soft as a breath, Quiet as death, Death with the face of love, Sings.......sings....... Voice with a trace of sadness, Sweeter than wine, Older than Time, She offers you escape, Fly...fly...fly... Don't let the sunlight find you, Or you will fade, And die......"