* ActingForTwo: Mai and the mysterious woman are both played by Yuumi Shida; this is even alluded to when Kouta mistakes the latter for the former. [[spoiler:[[SignificantDoubleCasting Turns out later on that they're one and the same]] - the mysterious woman is a time-traveling future Mai.]]
** Tomomi Jiena Sumi plays a member of Team POP UP and Jonouchi's assistant, Masako Suzuka/[[spoiler: Kamen Rider Sylphi]], it's unknown if they are the same person.
* ActorAllusion:
** In the Hyper Battle DVD, Kaito is shown to be a skilled chef; his actor Yutaka Kobayashi loves to cook and posts about his meals on the official Gaim blogs.
** This is not the first time when Tsunemori Aoki potrays [[Series/GaroTheOneWhoShinesInTheDarkness a character]] with [[TheStraightAndArrowPath bow]] as his weapon of choice.
** After Kyojiro Bando dispenses advice to Kouta, he just mentions that "I've been through quite a lot, you know." [[Series/KamenRiderRyuki Like two]] [[Series/KamenRiderKabuto previous series.]]
** It's not the first time Minori Terada portrayed the [[Series/KamenRiderDouble patriarch of a powerful family with hidden agendas.]]
* ActorInspiredElement: The producers were inspired to create Shapool because they noted that Kaito's actor in real life was someone rather happy go lucky and kind, the complete opposite of his character.
* CastingGag: While Kaito's actor turned down the role, his outfit bears some resemblance to [[Series/KaizokuSentaiGokaiger Captain Marvelous]].
** When he turns up in ''Gaim Gaiden'', Takatora and Micchi's father Amagi Kureshima is played by Minori Terada, who previously played Ryubee Sonozaki in ''Series/KamenRiderDouble''. As mentioned above, both characters are the patriarchs of families with a lot of power and a lot of skeletons in their closet.
* TheCastShowoff: Kaito's actor Yutaka Kobayashi is also a proficient baker in real life and this gets to show in both of his roles, be it Kaito (Hyper Battle DVD) or Shapool (Gaim Gaiden Baron).
* CrossDressingVoices: [[spoiler:Redyue, a female Overlord, is voiced by Creator/KenjiroTsuda, a male voice actor.]]
* FriendshipOnTheSet: Yutaka Kobayashi and Gaku Sano. Kobayashi even baked the cake for his wedding.
* IKnewIt:
** [[spoiler:The fruits turning people into Inves, and Yuya being the first Inves Gaim fought.]]
** [[spoiler:Takatora being alive. Both times.]]
* IronyAsSheIsCast: Yutaka Kobayashi (Kaito's actor) revealed that he actually hated bananas due to a time where he ran a marathon and only ate bananas that day. He overcame this dislike, since children would see him as "the banana guy." He's also physically klutzy with action and dance scenes and trips over constantly when even ''walking or running'', and apparently had only managed to get through the initial audition because [[https://twitter.com/cocopico21/status/1046221696607223810 he gave an evasive answer when asked if he could do action scenes]].
* NoExportForYou:
** South Korea skipped from Wizard to Drive. Presumably they didn't like the samurai motif.[[note]]It most likely would have gone against South Korean broadcasting standards, since Japanese media has heavy restrictions on its content, including specific cultural references unless they can be {{Bowdlerize}}d during adaptation and/or dubbing due to "some" cultural tensions between the two countries. It would be rather difficult to write off the samurai theme.[[/note]] Also, US skipped this show in favor of Drive.
** From this series onward, ''Kamen Rider'' has stopped all exporting to Singapore. There are multiple potential reasons for this, from the low local viewership/sales for ''[[Series/KamenRiderWizard Wizard]]'', the DarkerAndEdgier nature of the show, to fans' backlash over [[TheyChangedItNowItSucks the heavily-modified "Asian Version"]] release of ''Gaim'''s merchandise that was initially launched in Hong Kong.
* NoStuntDouble: Minami Tsukui portrays Yoko Minato/Kamen Rider Marika in both human and Rider forms and also performs her own stunts, though this is downplayed as she does have an understudy.
* TheOtherDarrin: [[spoiler:Kataoka Ainosuke VI does not reprise his role as Kohgane in the final episode.]]
* ProductionPosse: Of the three secondary writers who helped cowrite episodes with Creator/GenUrobuchi or wrote tie-in media like movies, only Nobuhiro Mōri is a regular Toei writer. The others are Urobuchi’s [[Creator/NitroPlus nitro+]] coworkers, Jin Haganeya and Gun Snark. Another nitro+ employee—Niθ—designed the Red-type Inves in the series and Megahex from ''Movie War Full Throttle''.
* PromotedFanboy:
** Creator/GenUrobuchi was a fan of ''Series/KamenRiderBlack'' and has stated he wants to recapture the excitement that series gave him when he saw it.
** Gaku Sano, who plays Kouta[=/=]Gaim, wished he could be a character in ''Series/KamenRiderKuuga'' when he was growing up, now he gets to be TheHero of the series.
** Shōnan no Kaze, the band doing the series theme song, are mostly either fans of the series or at least the previous bands that performed music for the franchise.
** The actor for Kaito[=/=]Baron, Yutaka Kobayashi, was a fan of ''Series/KamenRiderRyuki'' growing up. Ironically, he was not a fan of bananas, but worked to overcome this dislike after accepting his role as Kaito/Baron. He shares the surname and initial of his given name of Ryuki's head writer as well, Creator/YasukoKobayashi.
** Mitsuzane/Ryugen's actor, Mahiro Takasugi, has also stated in interviews that he is a ''Series/KamenRiderRyuki'' fan. Seems to be a common characteristic in the cast and crew behind ''Series/KamenRiderGaim''.
* PropRecycling:
** The costume for the Hekija Inves from #14 is merely the Byakko Inves's, with a different mask and without the spikes in the back. [[spoiler:Becomes a lot more meaningful once you find out the story behind these specific Inves.]]
** Same for #30's Yagi Inves, being modified from the Komori Inves's costume.
** Yomotsuheguri Arms is mostly just a repainted combination of Grape's armor and Kiwi's helmet.
** Kouta's outfit as [[spoiler:The Man of the Beginning]] is a modified version of Kiwami Arms' silver armor with a new chestplate(which itself is a recolored Kurokage chestplate) and cape. [[spoiler:This is justified as Kouta has now surpassed Kiwami Arms without even needing to transform]].
** Bujin Gaim is essentially a repaint of Gaim’s Orange Arms, with the armor painted red, and the mouth plate becoming black. He also uses the Blood Orange Lockseed, a red repaint of the Orange Lockssed with vines on the outside lock.
** Bujin Gaim was itself made into the Fresh Orange Arms used by Gaim in the Hyper Battle DVD.
** Duke's ''Gaiden''-exclusive Lemon Arms Lockseed is a repaint of Ryugen's Kiwi Lockseed.
** Special mention has to go to the apple-themed Arms, which take no less than four forms over the course of the series: Mars' Golden Arms, Kamuro's Silver Arms, Jam's Darkness Arms, and Idun[=/=]Baron's Forbidden Apple Arms. Jam's case is justified, as [[spoiler:he's actually Mars, and the Darkness Apple Lockseed is a depowered Golden Apple Lockseed.]]
** Gaim's Daidaimaru sword is wielded by two other Riders, Bujin Gaim (where it's red rather than orange) Jam (where it's purple).
** The stage shows introduce a comedy version of this with Gaim's Kabi (Moldy) Orange Arms, which is white with blue-green mold spots randomly applied.
** Kamen Rider Zangetsu Kachidoki Arms, the exclusive form to ''Kamen Rider Zangetsu Stage -Gaim Gaiden-'' theater stage show is reused and recolored from Gaim Kachidoki Arms. The Kachidoki Lockseed[[note]]which is based on an orange[[/note]] is painted green[[note]]representing a melon[[/note]].
** Also from the stage show, Maja's Arms and weapon are redecos of Kamen Rider Fifteen's suit and weapons.
** In the ''Gaim Gaiden'' movies, a few of the riders gain new items and forms.
*** Zangetsu Watermelon Arms is simply a repainted Melon Arms wielded a repainted Melon Defender with a [[GatlingGood Gatling gun]] mounted on it. The Watermelon Lockseed itself is, oddly enough, a repaint of Baron's Mango Lockseed.
*** Zack gets the Marron Enrgy lockseed and transforms into Knuckle Jimber Marron Arms. The Marron Energy Lockseed is a repaint of the Peach Energy Lockseed.
*** His Marron Bombers, when shed of the outer skin, are remolded from Kamen Rider OOO’s Sagozo Gori Bagoon gauntlets.
*** Oren is corrupted by the Helheim forest and his armor turns black, becoming King Durian Arms.
*** Jonouchi gets the Lychee lockseed and transforms into Lychee Arms, with a repainted Lord Baron Guronbaryamu sword and Donkachi. The Lychee Lockseed is an original Lockseed.
** Kamen Rider Saver is a kitbash of the Mars suit, with the helmet painted red and having mummy-like wrappings around it, and the armor is composed of the left shoulder from Blood Orange Arms, and the rest being comprise of the Ringo Arms. He uses the Blood Zakuro Lockseed, which is a repaint of the Suika Lockseed, and the Blood Orange Lockseed from Bujin Gaim.
** Kamen Rider Sylphi is a repaint of Idunn, with an additional veil on the helmet, and uses a retooled Kagematsu staff with a Helheim fruit on the top. The Hells Lockseed is an original Lockseed.
* RealLifeRelative: [[spoiler:Metal Yoshida, Oren's actor, and Hiromi Iwasaki, the Overlord Queen's actress, are husband and wife.]]
* RoleEndingMisdemeanor: While it didn't happen during the run of the show, the actor for Kaito Kumon (Yutaka Kobayashi) was fired from his agency after he was found out to have shoplifted 9000 Yen's worth of items from a convenience store.[[note]]Charges were dropped due the stolen merchandise being worth less than $100 and bail being posted for Kobayashi[[/note]] While he was allowed to record lines for the CSM Genesis Driver, his acting career has ended since with Kaito Kumon being his last role.
* WhatCouldHaveBeen:
** Zangetsu was supposed to be more of a rival to Gaim instead of Baron. This explains why they have the same transformation jingle and why Zangetsu was the only Armored Rider besides Kouta to have an upgrade (Kaito's Lemon Energy Arms was [[ThrowItIn added later]] because of his popularity).
** Knuckle had a faceplate designed, but since he uses a mass produced driver (which normally uses blank plates), it [[FridgeLogic made no sense]] for it to be used.
*** Speaking of Knuckle, [[spoiler:he was originally scripted to die fighting Kaito in #45, but was apparently saved by PopularityPower; even Gaku Matsuda didn't know until he saw the scripts for #46 and was overjoyed to find out that Zack survived. Heck, he probably wouldn't have gotten his own ''Gaiden movie'' if not for his PopularityPower.]]
** Remember the DJ Gun combining with the Musou Saber to create Taiken Mode? There was a rumored Kiwami-exclusive combination of the DJ Gun combining with the Daidaimaru in Naginata Mode, creating the [[DoubleWeapon DJ Sojinto]]. It never materialized.
*** Considering how trying to wield a potential weapon like that would've been impractical due to the majority of its mass being on one side, it was probably for the best.
*** In a related vein, if the toy version is accurate, the Kiwami Lockseed could summon Suika Arms' Suika Sojinto just like any other Arms Weapon. Presumably this didn't happen in the show because there'd be no way to show Gaim wielding a MiniMecha-sized twinblade without tons of CGI.
** The biggest offender was the absence of a Jinba Melon Arms. This did appear in the toyline due to the Arms piece being able to fold into four different sides for each of the original four Energy Lockseeds, but was likely abandoned on the show due to storyline reasons. [[spoiler:It finally appears in the ''Kamen Rider Gaim'' sequel novel, used by Takatora[=/=]Zangetsu himself.]]
** In an interview, Takatora's actor said that there would be "[[HotterAndSexier very wet]]" bed scenes in ''Kamen Rider Gaim Gaiden: Kamen Rider Zangetsu''. No such scene is in the final cut, likely due to content censorship. The closest we get is a KissingDiscretionShot.
** In-universe, alternative designs for Sengoku Driver including a water tap one and an eldritch looking one.
** People who pre-ordered the second ''Gaim Gaiden'' movie were sent a link to a special poll to vote on a third ''Gaim Gaiden'' movie, with options including all of the riders from the TV series other than Zangetsu and Baron[[note]]Ryugen, Gridon, Kurokage, Bravo, Gaim, Jam, Sigurd and Marika[[/note]], but a third Gaiden movie wasn't produced - had a third ''Gaim Gaiden'' movie pair been produced, not only could Knuckle and/or Duke have gotten a second ''Gaiden'' movie, but it's possible we could've seen the regular lockseed versions of the Cherry and Peach Energy Arms. For that matter, if Gaim had gotten a ''Gaiden'' movie, it's entirely possible that we could've actually seen Jimber Melon Arms on-screen. Presumably, a third set of ''Gaim Gaiden'' movies didn’t came about immediately due to the decision to focus on [=DTV=] movies for ''Series/KamenRiderDrive''.
*** Now moot, thanks to Gaim Gaiden: Gridon vs Bravo. This is the first movie to be produced in the Reiwa era to not be based on the show airing concurrent to or slightly before or after it.
*** Similarly, people who pre-ordered the first received a similar link for the second ''Gaiden'' movie, with the poll having Ryugen, Gridon, Kurokage, Bravo, Knuckle, Jam, Duke, Sigurd and Marika as options, and Duke and Knuckle eventually won said poll.
** Originally, Urobuchi had planned on having [[spoiler:Sid]] killed by Micchy instead of Rosyuo.
* WordOfGod: It's said that they did a lot of {{Mythology Gag}}s, such as the multiple Riders being a nod to Ryuki, or the omnipresent Yggdrasill Corporation mirroring ''Faiz'''s Smart Brain.
** Zangetsu is implied to an {{Expy}} of Kamen Rider Ouja, [[spoiler:though that could actually have been a foreshadowing of Zangetsu Shin II.]]
** Mitsuzane (Kamen Rider Ryu'''gen''') and Takatora (Kamen Rider Zan'''getsu''') are an {{Expy}} of [[spoiler:Shadowmoon and Series/KamenRiderBlack]].
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