Masaru Aso was the lab assistant of geneticist Doctor Mochizuki, used as one of his experiments related the creation of the Neo Organism, enabling him to transform into a grasshopper-like being called Kamen Rider ZO. He fled into the mountainside and went into a coma before he was awakened by a telepathic call two years later with an unconscious urge to protect Hiroshi Mochizuki, the son of Doctor Mochizuki.

Kamen Rider ZO

Kamen Rider World is a short 3-D film produced by Toei Company based on the Kamen Rider Series that premiered on August 6, 1994 and was shown in amusement parks and special events nationwide in Japan. It was shown as a triple feature alongside Super Sentai World and Toei Hero Daishugō (a crossover between Tokusou Robo Janperson and Blue Swat which also used footage from Super Sentai World).

Kamen Rider World

Iwatsuki Reiko, a writer for a weekly magazine goes on a trip to Amakusa, Kyushu with Yukitake Asami, the president of a company. Yukitake informs Iwatsuki that she has many enemies.