According to an interview with director Luigi Cozzi, the movie wasn't planned as a sequel to Hercule (1983). He was asked by the producers Menahem Golan and Yoram Globus to film scenes for Les 7 gladiateurs (1983) to save it. After they saw what he filmed, they asked him to write a story around the scenes, and make a few more with Lou Ferrigno, not telling him that he was involved in a sequel to Hercule (1983).
The film has only 35 minutes of new scenes with star Lou Ferrigno. The remainder of his screentime is reused footage from the previous Hercules film.
The fire monster called up by the high priest is reminiscent of the Monster from the Id from the movie Forbidden Planet when it first appears.
Margie Newton found it difficult working on Les aventures d'Hercule (1985) since she was acting in the film and L'ultimo guerriero (1984) simultaneously. She hardly slept since she was working on "The Final Executioner" in the day and "The Adventures of Hercules" in the night. She lost 10 pounds and became anorexic due to the strenuous shooting schedules. That said, she enjoyed working on both films and found them to be great experience for her.
Lou Ferrigno had his lines dubbed (or had someone else provide voiceover) due to his speech impediment from being deaf. This impediment is often referred to as "deaf speech." It is a particular voice pattern because deaf people are unable to hear their own voice, thereby they are not able to make vocal and speech sounds the same way hearing people do.