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. After Kyoryuger concluded on February 9, 2014, Kamen Rider Gaim was joined in the Super Hero Time lineup with Ressha Sentai ToQger. After the finale of Kamen Rider Gaim, Kamen Rider Drive joined ToQger on the Super Hero Time block. The catchphrase for the series are "It's a Rider Warring (Sengoku) 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 mysterious monsters 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 Armored Rider Gaim. He must fight the sudden appearance of the Inves, but also against other the armored-Kamen Riders known as 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.
The episodes in this Kamen Rider Series incorporate the name of fruit somewhere early on in the series, as well as 2 exclamation points in the title also early on, one for the exclamation, and the other for the other half of the episode title. Episode 30 takes place between Episode 28 and Episode 29, serving as a promotional episode.
The series is divided into five story arcs titled Sagas (編,Hen), much like a manga/anime series.
This is the first Kamen Rider series to fully utilize the "A Rider can use other Riders' powers" idea more freely than Kamen Rider Decade. While Decade has to be acknowledged by the Riders themselves to use their powers, Gaim Riders only need the Lockseed and appropriate Driver, if not already in their possession.
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, 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.
After episode 32, the series' story becomes something similar to Kamen Rider Hibiki and Ryuki's USA adaption Kamen Rider Dragon Knight, where most of the Riders are gathered in the form of an alliance, with one or more other Riders acting as or aligned with a villain.
Excluding stage show exclusive and A.R. World Riders and counting based on on-screen appearance, Gaim held the record for the most Riders to appear at 24, one more than Hibiki and 9 more than Ryuki.
In addition to Gen Urobuchi serving as head writer, several of his coworkers from the company nitro+ were involved in the production of the season. Although Gaim-related material does not officially bear the company’s name, nitro+ has acknowledged it as one of their coproductions in events such as convention panels.