Based on the Italian comic book by the same title. The book peaked in Italy through the 1960s and 1970s, and it is still published.
The plot of the movie is inspired by the third volume of the original comics, "L'arresto di Diabolik" (The arrest of Diabolik), and its Remake, in which Diabolik tries to steal the famous Pink Diamond, and so meets his future partner and lover, Eva Kant
Claudia Gerini, who plays Mrs. Morel, had already appeared in another project based on DIABOLIK: she portrayed Eva Kant in the music video of the song "Amore Impossibile" (Impossible Love), by Italian band "Tiromancino". The video was directed by Lamberto Bava, son of Mario Bava, director of the 1968 movie version of DIABOLIK. In that same video had a cameo also John Phillip Law, who played Diabolik himself in Bava's movie.
This was the last screenplay by Michelangelo La Neve, a frequent collaborator of the Manetti Bros., and he himself a comic book writer, having written for the most famous Italian comic series like "Dylan Dog" and "Martin Mystère".
Diabolik, played by Luca Marinelli, blinks only a handful of times throughout the movie. One notable exception is the trial scene, where he blinks his eyes to spell a Morse code message for Eva.