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.
Hiroshi Tsuchikado
as Masaru Asou / Kamen Rider ZO
ささきいさお
as Doctor Mochizuki
Shohei Shibata
as Hiroshi Mochizuki
犬塚弘
as Seikichi Mochizuki
森永奈緒美
as Reiko
大葉健二
as Kuroda
山下優
as Nishimura
Iori Sakakibara
as Miyazaki
Shingo Yuzawa
as Neo Organism / Doras (voice)
