KIKAIDER 00 (キカイダーダブルオー Kikaidā Daburu Ō, Kikaider Double O) is a S.I.C. Official Diorama Story by Masato Hayase and published in the Hobby Japan magazine from January 1999 to January 2002. Coinciding with the releases were special figures and dioramas by S.I.C. preceding the S.I.C. Hero Saga. It tells an original story that serves as a sequel to the TV version of Android Kikaider and Kikaider 01, also introduces a previously manga exlusive character, the title protagonist Rei (Kikaider 00). Characters from other Ishimori Productions series such as Robot Detective K and Kamen Rider V3 have appeared in some chapters.
During a rainy night, lightning struck a church Dr. Komyoji was staying at. Outside, he saw a cross on the roof of the church, there is a familiar red and blue android with clear parts. It is the new Kikaider "00", which it ’s the Kikaider that Dr. Komyoji saw for the first time in about 30 years.
However, Green Mantis appears to follow it. In Jiro's absence, a new organization called XASH had surfaced and Rei must fight against them.