Kamen Rider Gaim (仮面ライダー鎧武(ガイム),Kamen Raidā Gaimu?) is a Japanese tokusatsu drama in Toei Company's Kamen Rider Series, it is the fifteenth series in the Heisei period run and the twenty-fourth series overall. Toei registered the copyright and trademark of the series, which started on October 6, 2013, joining Zyuden Sentai Kyoryuger in the Super Hero Time line-up three weeks after the finale of Kamen Rider Wizard. Starting on February 16, 2014, Kamen Rider Gaim was joined in the Super Hero Time lineup with Ressha Sentai ToQger. After the finale of Kamen Rider Gaim, Ressha Sentai ToQger aired alongside the next Kamen Rider series, Kamen Rider Drive. The catchphrase for the series are "It's a Rider Warring era." (ライダー戦国時代。,Raidā Sengoku Jidai?) and "How would you use your power?" (キミはこの力どう使う?,Kimi wa kono chikara dō tsukau?).
Because of the large company, Yggdrasill Corporation setting up shop in the once bustling city of Zawame (沢芽市,Zawame-shi?); the community started to become more like a jōkamachi (城下町,castle town?). To escape the feeling of being under castle authority, dance crews were formed by young people to bring joy back to the public. Along with this is a popular game that uses the mysterious Lockseeds that contain animals called Inves that are said to come from another dimension.
As the game becomes more popular, tears in reality begin to open that bring the Inves from their home dimension to Earth. Kouta Kazuraba, a young man who recently quit his dance crew Team Gaim (to help his sister Akira Kazuraba), finds a special Lockseed and the Sengoku Driver to become an Armored Rider, named Kamen Rider Gaim. He must fight the sudden appearance of the Inves, but also against other Armored Riders, effectively becoming a Sengoku period-like conflict for only one victor to prove themselves that they have the right to possess the power of the Helheim Forest, the proverbial forbidden fruit. But while adamant to obtain the Golden Fruit to save the world, Kouta's goal involves him having a predestined confrontation with Kaito who desires the fruit's power to shatter the status quo of the world.
This is the first Kamen Rider series to fully utilize the "A Rider can use other Riders' powers" more freely than Kamen Rider Decade. While Decade has to be acknowledged by the Riders themselves to use their powers, Gaim Riders need the lockseed and appropriate driver, if not already in their possession.
This is the first Kamen Rider series since Kamen Rider Kiva whose title is not an English word nor based on an English word.
While the Gaim Riders' motif is fruit, it is not the first series to have a Rider with a fruit motif. The first one is Kamen Rider Den-O, with the peach-themed Sword Form.
This Kamen Rider series does not intend to strictly follow the two-episode story arc structure that has been part of the Kamen Rider franchise since Den-O.
Most of the Riders' Transformation segments are similar to the Riders from Den-O.
Coincidentally, the voice for one of the Drivers and the Narrator are former Imagin voice actors from Den-O.
With a total of 20 Riders plus the Kurokage Troopers, Gaim not only has more Riders than any Neo-Heisei series, but has beat Ryuki (which had a total of 13 Riders, along with the 2 Alternatives), Kabuto(which had 11 Riders, not counting ZECTroopers), and Hibiki (which had 19 Riders, however it had more if you count the novel and S.I.C. saga) which makes Gaim the series with the most Riders seen on screen with 21 Riders.
Interestingly before episode 32, this series is more focused on Kamen Riders battling each other than Kamen Rider Ryuki.
Later since episode 32, the series' story becomes something similar to Ryuki's USA adaption Kamen Rider Dragon Knight, where most of All Riders are gathered in form of an alliance, with one/another Rider(s) on a villain sides.