Prior to the original story being written, Toho held story meetings to discuss ideas. One of the ideas included to have Mothra emit a ray beam. While writing the original story "The Glowing Fairies and Mothra", Nakamura chose a giant moth because he wanted a creature that underwent a transformation. Producer Tanaka later confirmed that the female perspective for the film was suggested by another producer during the early planning stages. This inspired Tanaka to come up with the idea for the Shobijin and their roles as guardian spirits of a South Seas island. The character Zen'ichirō Fukuda was named after the writers of the original story.