Tia Carrere, Roy Brocksmith, Sven-Ole Thorsen and Pat Roach have all worked with Arnold Schwarzenegger. Kull the Conqueror was originally going to be the 3rd Conan film "Conan the Conqueror" with Schwarzenegger reprising the role of Conan the Cimmerian.
The famous "With this axe, I rule!" line at the end of the movie is actually the title of a Robert E. Howard short story about Kull, which was rejected by Howard's then primary publisher, "Weird Tales" magazine. He later rewrote and sold the story as "The Phoenix on the Sword", the first Conan story, which makes the item that this project was initially developed to be a "Conan" film somewhat ironic.
"Kull the Conqueror" was originally going to be the 3rd Conan film "Conan The Conqueror" and would be an adaptation of the novel by Robert E. Howard. Which a 45 year old Conan, now King of Aquilonia, learns of a group of conspirator's plot to depose of him, by resurrecting the ancient sorcerer from the pre-Hyborian empire of Acheron, Xaultotun.
Akivasha's line, "I am altering our bargain. Pray I don't alter it any further!" is a corruption of Darth Vader's "I am altering the deal. Pray I don't alter it any further!" from Star Wars: Episode V - The Empire Strikes Back (1980).
In the Finnish translations of the Kull stories, the character name 'Kull' was changed into 'Kall' to avoid unintentional comic elements (there is a Finnish word meaning 'penis' that resembles 'kull' quite a bit). This, however, was not done with this movie, adding its part to the unintentional comedy.
One of the film's taglines is "Son of Conan". Although Conan and Kull were characters created by Robert E. Howard, Kull of Atlantis, in the original stories, came from pre-cataclysmic Atlantis c. 100,000 B.C and Conan the Cimmerian was from the ancient Hyborian-age, after the destruction of Atlantis and before the rise of the ancient civilizations. This means Kull came before Conan and the two characters are father and son and Conan's father was a Cimmerian blacksmith.
The trivia item below may give away important plot points.
The dead man from whom Kull takes the axe in the cave of the god was supposed to be Kull's father, but this idea was scrapped before the film was actually shot (although it remains in the movie's novelization).