is a 2010-2011 Japanese tokusatsu drama in Toei Company's Kamen Rider Series, being the twelfth series in the Heisei period run and the twenty-first overall. It began airing on September 5, 2010, the week following the conclusion of Kamen Rider W, joining Tensou Sentai Goseiger and then Kaizoku Sentai Gokaiger in the Super Hero Time lineup, until its conclusion on August 28, 2011. The series' titular Kamen Rider made a cameo appearance in the film Kamen Rider W Forever: A to Z/The Gaia Memories of Fate and a supporting character in other Kamen Rider movies. Production The Kamen Rider OOO trademark was registered by Toei on April 8, 2010. OOO is written by Yasuko Kobayashi, known for the screenplays of Seijuu Sentai Gingaman, Mirai Sentai Timeranger, Kamen Rider Ryuki, Den-O, and Samurai Sentai Shinkenger. The creature designers are Yutaka Izubuchi, known for his work on the Lords in Kamen Rider Agito, and Tamotsu Shinohara, known for his work on the Mirror Monsters of Ryuki, the Orphnoch of Kamen Rider 555, and the Fangires of Kamen Rider Kiva. Unlike several previous Heisei Rider Series, no alternate name has been given yet for the three O's in the title ( read as "Double" and read as "Φ's/Phi's/Faiz") aside from an alternate spelling of the name of the main Kamen Rider: Ooz. Both "OOO" and "Ooz" are intended to be read as "O's", referring to the multiple uses of the letter O in the title as well as . The title OOO signifies the three medals that the main Kamen Rider uses to transform as well as being representative of the infinity symbol () with an additional circle. The 28th episode of Kamen Rider OOO serves as the 1000th episode of the Kamen Rider Series since Kamen Rider premiered on April 3, 1971. The episode was originally set to premiere on March 27, 2011. However, due to the 2011 Tōhoku earthquake and tsunami, the airing of this episode was postponed by one week to April 3, 2011. For the 999th and 1000th episodes, various guest stars with the kanji for in their name were featured: Chiaki, Chisato Morishita, Chinatsu Wakatsuki, and the owarai duo Harisenbon (sen also being Japanese for 1000). Story Eiji Hino is a traveling man who has no place to call home and a tragic past. When metallic creatures known as the Greeed awaken after their 800-year slumber to attack