Kamen Rider OOO: The Medals of Ikki Tousen a crossover made by Kamen Rider Chrome and Ten-Faced Paladin (the same creators from Showa and Vampire, Love Hina Double Trouble and Rosario to Kiva) that focuses on Kamen Rider OOO and Ikki Tousen. This is also the first official Kamen Rider OOO fanfic. It was released on October 25th 2010.Taking place during the Dragon Destiny saga, the Greeed escape from the Kanto Art Museum, very much in the same manner as the first cold opening in OOO. Moments later, a crowd is gathered in front the museum, Hakufu and Kokin among them, wondering if it was a robbery. Hakufu soon finds the red Core Medal, obviously attracting Ankh's attention. But when Yummies appear in the city, and turn out to be capable of overpowering top Fighters such as Saji, Ryomou, and Chou-un, Ankh has no other option but to allow Hakufu to become Kamen Rider OOO to stop the rival Yummies. But just how will this affect the destiny of the Fighters?
Another collaboration from KR Chrome and Ten-Faced Paladin, and idea from Tailsmo4ever. When the Greeed awaken, the Fighters will face a threat that is as ancient as they are. Now, an ancient hero must rise again to fight the threat of the Greeed.