Rose Hobart was cast in the film, but Boris Karloff became ill and the production had to be shut down until he recovered. By the time he returned, she was working on another film and was replaced. However, Hobart said in a 1984 interview that she can still recognize herself in long shots.
A vorvolakas (also vrykolakas) occurs in Greek folklore as an undead creature capable of causing harm to the living. Its characteristics are similar to many other characters of legend, but it is most closely associated with vampires. In Hollywood movies such as Dracula (1931), the word vampire is often translated to Greek as vrykolakas. However, traditional vorvolakas are not noted for blood-drinking.
The war mentioned in the film is the First Balkan War of 1912-13. Greece, Bulgaria, Serbia and Montenegro fought against the declining Ottoman Empire.
The 19th century artist Bocklin painted "The Isle of the Dead." It appears in the credits of this film and is recreated in the sets.
Sergei Rachmaninoff composed an orchestral piece titled "The Isle of the Dead" in 1908, also inspired by the Bocklin painting.