is the theatrical film adaptation of the Japanese 2008 Kamen Rider series, Kamen Rider Kiva, directed by Ryuta Tasaki and written by Toshiki Inoue. A director's cut came out in June 2009.
The film is produced by Ishimori Productions and Toei, the producers of all the previous television series and films of the Kamen Rider series. Following the tradition of all Heisei Kamen Rider movies, it is a double bill with the movie for 2008's Super Sentai series Engine Sentai Go-onger, Engine Sentai Go-onger: Boom Boom! Bang Bang! GekijōBang!!, both of which premiered on August 9, 2008. The film's title is translated into English as Masked Rider Kiva The Movie: King of the Castle in the Demon World. The double-feature opened at number 4 in Japanese box offices its opening weekend.
Production
King of the Castle in the Demon World features two new Riders, the first of which was shown in silhouette in Japanese children's magazines, Kamen Rider Rey, who is a monster hunter named Takato Shiramine played by Shouma Yamamoto. He is partnered to Rey Kivat, voiced by Norio Wakamoto. The villain of the movie is Takashi Sugimura who is a death-row inmate and transforms into the black and horned Kamen Rider Arc, portrayed by Ken Horiuchi of the comedy troupe Neptune. Arc is to be the tallest Rider without the use of powers at 3.2 m tall. Also guest starring is Gal Sone, who plays a Medusa-like villainess named Sayaka who, among other creatures known as the Legendorga, aids Arc in his quest to rule the world. As part of the role, Gal Sone will show off her competitive eating skills. Toshihiko Seki, Kōji Yusa, Masaki Terasoma, Kenichi Suzumura, Rina Akiyama, and Ryo Ueno of the Den-O cast are all to have cameo appearances in the film.
Story
The story begins in 2008 as the Antlion Fangire begins to feed at an exhibit room until Megumi intervened as Nago arrives to slay the monster. However, during their struggle, the Mummy Legendorga suddenly resurrects and feeds on the humans before using his power to turn the Antlion Fangire into his slave to aid him in overwhelming Nago with the Arms Monsters watching the fight. While this occurred, Wataru Kurenai starts attending a local high school at Shizuka's suggestion after a welfare officer visited him and quickly befriends Natsuki Tsukue, who tries to get Wataru to join several clubs where he fails in each one while trying to ask her if she would like to start a violin club after hearing her play, she refuses out right.
Later that night, death row inmate Takashi Sugimura escaped from prison and the pursuing police officers by means of a dark power possessing him, with Nago going after him under advisement from Mamoru Shima to capture the fugitive with caution as he may be a Fangire. When Nago finds Sugimura, he chases the fugitive all the way to Wataru's high school and takes Natsuki hostage, but she is freed by the joint efforts of Wataru and Nago. However, the Medusa and Mummy Legendorgas appear to Sugimura's aid when he was being escorted back to jail, overpowering Ixa as Kiva arrives. They overpower the riders until another figure named Takato Shiramine appears, transforming into Kamen Rider Rey and driving the two Legendorgas off as they take Sugimura with them, waking him as their Lord.
At the cafe, as Shiramine explains the Legendorgas, Wataru finds that the current crisis started when Sugimura attempted to break out of jail by using the famous violinist Towa Sakakibara as a hostage in 1986 and broke the Legendorgas' seal. With this knowledge, Wataru asks the Arm Monsters permission to use Castle Doran's Time Door to go back in time to prevent Sugimura's actions. While trying to get Sakakibara to cancel her concert, he is stopped by Otoya, who was convinced he was a Fangire and tries to beat him. After another attempt to talk to her, Wataru is attacked by Yuri after Otoya tells her about him as the police arrive to arrest Otoya on the impression he is the criminal. Forced to take Wataru in a stolen police car, Otoya is shocked when Wataru recognized him as his father. Wataru attempts to prove himself with his cellphone and money before he and his father are both sent to Kanto West Prison where Towa is to perform as Sugimura takes her hostage to escape. But Otoya knocks out a guard named Sanjou so he and Wataru can get out of their cell to save Towa and restrain Sugimura.