Film / Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders

Spoilers for all preceding Kamen Rider entries, including Kamen Rider Ex-Aid: True Ending, will be left unmarked ahead. You Have Been Warned!

Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders is the ninth film in the Kamen Rider franchise's annual "Movie War" crossovers.

Besides featuring Kamen Rider Ex-Aid and Kamen Rider Build, this film also marks the return of several veteran Riders: OOO, Fourze, Gaim, and Ghost. The name suggests that it was intended be the last Heisei era Movie War film due to diminishing box office returns and the then-upcoming abdication of Emperor Akihito (Heisei); what actually happened requires a bit of explaining. ^note As the movie was being developed, Akihito's abdication was seen as almost certain, but a specific date wasn't announced; nevertheless, the movie was titled as such due to Ex-Aid still having a bit to go when the abdication was approved by the Japanese Diet. The date was announced a week before this movie's release as April 30, 2019; well into the run of the season after Build and, presumably, later than Toei expected. Ultimately, Kamen Rider Zi-O would be announced as the final Heisei Rider, along with the actual final entry in the Heisei-era film series: Heisei Generations FOREVER.

Trouble strikes the parallel worlds of Build and Ex-Aid when a new enemy, Bugsters infused with Nebula Gas, appears and begins attacking the populace. Sento Kiryu, Kamen Rider Build, fights them off using a mysterious power he thought was only a dream, while Emu Hojo can't become Kamen Rider Ex-Aid because a mysterious Kamen Rider appeared and drained his powers a week earlier. As the two worlds begin to collide, it'll take the combined efforts of Sento, Emu, their allies and their Rider precursors to save everyone.

---

Tropes exclusive to this movie:

• A God Am I: As per usual for Ex-Aid, Kuroto Dan still insists upon being called a god, and Onari takes advantage of being a former priest to butter him up and obtain the Build Gashats the Doctor Riders need.
• Alliance of Alternates: The Big Bad Duumvirate is a team up of Kaisei Mogami from the main Heisei universe and the Build universe.
• Alternate Self: The movie's Big Bad Duumvirate are Kaisei Mogami, who's an amoral Mad Scientist in either world; the main difference is his employer (Foundation X in Ex-Aid's world, self-employed after being fired by Touto Institute in Build's world) and their personality (Mogami from Ex-Aid's world is more eccentric while Build's is more reserved).
• Apocalypse How: Mogami's plan is Class X, since the two Earths will be destroyed by the merger. It might go further than that, but the ramifications of the merger beyond Earth are never really discussed. The Mogamis don't care either way, as by the time that happens they'll be an immortal and omnipotent entity who can then become a Multiversal Conqueror.
• Back from the Dead: Ankh's broken Core Medal enters his clone and allows him to possess it and take it over. Sadly it's only temporary, but it gives Eiji further hope he can be restored permanently.
• Badass Teacher: Gentaro is a teacher at present.
• Big Bad Duumvirate: The Kaisei Mogamis are responsible for everything and are the main villain.
• Big Damn Heroes: The Legend Riders' primary purpose in this movie seems to be coming in at the exact moment Sento, Emu, and the others need help.
  • Takeru arrives to protect Emu and the others from Right Kaizer.
  • Eiji arrives to help Emu pull Banjou up from a deadly fall.
  • Gentaro saves Emu and Banjou from Right Kaizer bringing a roof down on them.
  • Kouta arrives to reveal the Enigma cloaking device, and takes on a horde of guardians to give Sento and Parado time.
• The Bus Came Back:
  • Eiji, Ankh, Gentaro, JK, Ohsugi, Kouta, Takeru, and Onari.
  • Foundation X returns in a major antagonistic role for the first time since Fourze, their last appearance having been a cameo at the end of Ex-Aid's "Beast Rider Squad" special.
• Call-Back: Quite a few.
  • The events of this movie follow directly after Build's Early-Bird Cameo in the post-credits scene of True Ending, with him stealing Emu's powers in that movie being a plot point. Build's encounter with Genm in the penultimate episode are also a plot point.
  • Kamen Rider OOO: Eiji is still Walking the Earth with Ankh's broken Core Medal, and ends up being the one to tell the Ex-Aid and Build characters about Foundation X because he's dealt with them before.
  • Kamen Rider Fourze: This movie takes place in the "five years later" timeframe established by Movie War Ultimatum, and the former Kamen Rider Club members all have the jobs they had in that movie: Gentaro is a teacher, JK is a reporter, and the latter mentions that Yuki is an astronaut and Kengo is acting as her mission control.
  • Kamen Rider Ghost: Onari left the Daitenkuu Temple to form his own paranormal investigation business, as seen in direct-to-video RE:BIRTH: Kamen Rider Specter movie. At the ending of this movie, he rejoins the temple.
  • Foundation X still has the technology to create their own Core Medals and Astro Switches, as they did in Movie War Mega Max, which lets them create copies of the Greeeds and Horoscopes.
• Call-Forward: Takumi Katsuragi was involved heavily in the early development of Enigma, and a very similar but less destructive plan to merge two worlds is the cornerstone of the last act of Build.
• Cast Calculus: The Ex-Aid cast sans Parado interacts with most of the returning characters and Ryūga, while Parado spends some time with Sento and most of the Build cast in their world and meets Kouta.
• Catchphrase: Played for Laughs: Before the final battle, Emu starts to deliver a variation of one of his phrases ("The fate of the two worlds… we'll change it!"), but the last part is ruined by the other five Riders shouting their own Catch Phrases over him. They then have a brief squabble over it. Eiji is also retroactively given a catchphrase of his own for this scene despite lacking a proper Pre-Asskicking One-Liner in his own series.
• Continuity Nod:
  • When Mogami summons copies of the Greeeds, Mezool's copy is spawned while sitting on the shoulders of Gamel's copy, a nod to the surrogate familial relationship the original characters had in OOO.
  • Ankh giving his Core Medals to Eiji so Eiji can use TaJaDor and the OOO Driver announcing the transformation with Ankh's voice is something that happened in the finale of OOO.
• Dimensional Traveler: Kouta is capable of traveling between worlds completely of his own power. This is because he's literally a god and the Helheim Forest is interdimensional.
• Drama-Preserving Handicap:
  • The Ex-Aid riders, whose Gashat-based powers are the only things capable of harming the Nebula Bugsters, are unable to transform for significant portion of the movie because the Enigma's activation caused them to malfunction.
  • The Nebula Bugsters are invincible to attacks from any Riders other than the Ex-Aid ones, but because they're fuel for the Enigma, the villains switch to using Guardian legions and replicated monsters right when most of the other past Riders are about to start fighting, giving them foes they can actually hurt.
  • Emu spends most of the movie without access to his powers because Build stole them to create the Ex-Aid bottle when he appeared at the end of True Ending. Without Hyper Muteki's invincibility, the heroes end up struggling quite a bit.
  • Sento doesn't use RabbitTank Sparkling until the final battle because Banjō took it early on to try it out for himself, but ended up getting trapped in the World of Ex-Aid and unable to give it back until they reunite.
  • A brief one for Eiji being unable to transform initially, as the movie acts as if the Core Medals being lost to oblivion after the finale of OOO is still in effect, despite him regaining the Core Medals in MegaMax and using them in subsequent appearances. Eiji ends up using Core Medals stolen from Foundation X's Greeed copies in place of his usual ones.
• Dynamic Entry: Kouta makes his entrance by destroying the Build World's Enigma's cloaking device with a jumping kick. Untransformed.
• Early-Bird Cameo: As is Movie War tradition, Kamen Rider Grease appears in a Post-Credits Scene where he steals the Phoenix and Robot Fullbottles from Build and sets up his appearance in the series proper.
• 11th-Hour Superpower:
  • Played with regarding Build's RabbitTank Sparkling form. Sento has already finished the Transformation Trinket at the start of the movie, but Banjou takes it because he wants to try using it. Then he gets sent to the World of Ex-Aid, and doesn't get the opportunity to return the Fullbottle until the middle of the Final Battle.
  • Hyper Muteki ends up being this since Emu spends much of the movie without access to his powers until Sento gives him the Doctor and Game bottles before the climax.
• Evil Is Hammy:
  • Kaisei Mogami from the World of Ex-Aid is very bombastic and unrestrained, in contrast to his World of Build counterpart.
  • Although he's still nominally on the heroes' side at this point, Kuroto's hamminess and god complex have not slowed down one bit.
• Flashback Nightmare: At the start of the movie, Sento has a dream where Build attacks Ex-Aid and drains his power, but he doesn't remember doing that. Eventually he figures out that it must have been Takumi Katsuragi using the Build Driver, and hypothesizes that holding onto the Ex-Aid Fullbottle allowed him to see the memory somehow. The movie doesn't cover the true reason, namely that Sento is Katsuragi, which will be revealed in the episode that immediately follows this movie.
• Flawed Prototype: The Kamen Rider Build Gashat created by Kuroto Dan is untested, which causes it to deal backlash damage to its users and cancel their transformations after a while. This means that the Doctor Riders mostly end up fighting the Nebula Bugsters un-transformed with their Gashacon Weapons.
• Foreshadowing: The main plot of the film is that both versions of Kaisei Mogami want to merge both worlds into one, this would foreshadow the final arc in Build in which the heroes would do the same by merging their world with one without the Big Bad in it to erase them from existance.
• Fusion Dance: The Bi-Kaiser from the film's final act; unlike the Hell Bros from Build, the two Mogamis actually combine into a single being, with the transformation sequence showing half their bodies seemingly burning away before they merge and then the Kaiser suit appears.
• Godhood Seeker: Kaisei Mogami's ultimate plan is to become an immortal "emperor" by merging his two alternate selves into a single being. Sento thwarts this by throwing off the timing.
• Gratuitous English: The World of Ex-Aid version of Mogami is fond of saying, "funky," which may be the reason the Nebula Steam Gun says it as well.
• Half the Man He Used to Be: The World of Build version of Mogami had the left of his body replaced with cybernetics after Enigma was activated by accident when he struggled with Takumi Katsuragi and the energy fried him. When the two finally merge, both get half their body vaporized and while the other merges with their alternate self's remaining half.
• Hand Wave: In order to patch a potential Plot Hole between Movie War Ultimatum and this movie^note In the former, Gentaro destroys the Fourze Driver in order to motivate his student Saburo, yet he obviously has it in the latter, FINAL's director said that the events of this movie take place the day before Ultimatum. (He also admits that he'd forgotten about that.)
• History Repeats: Once again, a scientist for Foundation X ends up having their own universal conquest ambitions besides the group's own goals and taking advantage of the Foundation's resources to achieve them.
• Homage: Continuing the tradition of old Ishinomori characters getting revamped versions in movies involving Fourze, the design of the Enigma, a giant mecha demon hand with an ominous eye in its palm, is a tribute to Dark General Gaburin from Space Ironmen Kyodain.
• Infodump: Soichi Isurugi only really appears in the movie to tell Sento about the Nebula Bugsters and Kaisei Mogami, then walks off and leaves everything else to the Riders.
• Kryptonite Factor:
  • Since the Nebula Bugster were made from a combination of two worlds' elements, the only way to fight them is with a combination of those elements: Build has to use the Ex-Aid Fullbottles in order to harm them, while the Doctor Riders have to use a Build Gashat to protect their equipment from the Nebula Gas.
  • Nebula Gas is shown to have a negative effect on the Gamer Drivers and Gashats. Parado also becomes weak when he uses the Game Fullbottle to communicate with Emu.
• Medley: The "Heisei Generations FINAL Special Medley" plays over the film's end credits, combining the six featured shows' opening themes: "Be The One", "EXCITE", "Warera Omou, Yue Ni Warera Ari", "Switch On!", "JUST LIVE MORE", "Anything Goes!", and going back to "Be The One" for the finish.
• Mooks: Nebula Bugsters are a variant of the generic Bugster Viruses which have been mutated by the Nebula Gas from Build's world.
  • Foundation X brings forth their own army of Guardians, the robotic foot soldiers from Build's world.
• Multiversal Conqueror: The Mogamis intend to become this after merging into Bikaiser and becoming an all powerful “Emperor”.
• Nigh-Invulnerable: The Nebula Bugsters are extremely durable compared to most Mooks and shrug off nearly anything thrown at them. However, they have a Kryptonite Factor to anything else derived from the Bugster virus, i.e. Gashats, Gashacon Weapons, and Legend Rider devices based on Ex-Aid. Even without transforming, Parado is able to fight off some Nebula Bugsters with much more success than Build and Cross-Z initially did.
• Non-Indicative Name: Despite its name, it's not the final Heisei Generations movie. Kamen Rider Heisei Generations FOREVER is.
• Non-Serial Movie: Unusually and aggressively averted. Build explicitly calls back to this movie when Seito brings in its own version of the Kaiser System used by the Mogamis, for Ex-Aid it acts as a side story that follows up on the ending of its summer movie and Build's cameo in the penultimate episode, and most of the supporting Riders continue their post-series storylines from previous films.
• One-Man Army: OOO, Fourze, Gaim, and Ghost vs. a gigantic army of Guardians. The Guardians never had a chance.
• Physical God:
  • Gaim is, as in the end of his series, a god ruling a distant planet. Showcased when he is the only character who can go back and forth between the worlds without the Enigma, and manages to destroy the World of Build's Enigma's cloaking field with one kick (which took Fourze throwing two exploding Horoscope Zodiarts into it to destroy the field around the main universe's version) while untransformed.
  • The Mogamis' endgame is to become this and then become a Multiversal Conqueror.
• Power Nullifier: The Enigma's presence in the World of Ex-Aid emits slight traces of Nebula Gas that causes the Gamer Drivers and Gashats to malfunction. The Kamen Rider Build Gashat that Kuroto made is required to protect them from this while the Enigma is active.
• Red Oni, Blue Oni: The two Mogamis. The blue oni is Kaisei Mogami from the World of Build, a Soft-Spoken Sadist and far more restrained than his World of Ex-Aid counterpart, the red oni, who definitely qualifies for Evil Is Hammy. Fittingly, World of Build's Mogami is the blue-colored Left Kaiser while the World of Ex-Aid's Mogami is the red-colored Right Kaiser.
• Series Continuity Error: While the film generally averts being a Non-Serial Movie for all the involved seasons, there are a few hiccups.
  • While the Hand Wave that Fourze's appearance in this takes place before he loses his powers in first act of Movie War Ultimatum is consistent with this movie's release date in 2017 when that part takes place, it indirectly contradicts the official statement by Word of God that Build's cameo in the post-credits scene of the True Ending movie takes place a year after the rest of the movie and the Ex-Aid series, since that would place the scene and this movie in 2018 after Fourze's powers are lost. The assistant director had to declare a retcon saying that the movie takes place the day before the first act of Ultimatum.
  • Eiji is implied to not have any Core Medals with him when he initially appears in this movie, and is only able to transform after Ankh pilfers some of Foundation X's artificial Core Medals from Mogami's Greeed clones. While this matches the status of the Medals at the end of OOO, it seemingly ignores the fact that Eiji regained the Core Medals during Movie War MegaMax. Further complicating this is that Eiji's familiarity with Foundation X in this movie can only be explained by his previous encounter with them during MegaMax.

• Shut Up, Hannibal!: During the final battle, the Riders deliver a joint version of this to the fused Mogami, essentially telling him that he can't beat them because a Kamen Rider's power comes from their friends and the people they protect.
• Start X to Stop X: Sento and Emu activate Enigma, which confuses the rest of the cast at first. However, during the final battle it turns out that by activating it early before the time When the Planets Align, they ensured that Mogami's fusion wasn't at full power and he could be defeated.
• This Cannot Be!: Bikaiser's response to Ex-Aid and Build overwhelming him and how they did it.
• Trapped in Another World: Kaisei Mogami uses the Enigma to trap Banjō in the World of Ex-Aid. Meanwhile, it's revealed that after Build stole Emu's powers, Parado chased him through the Enigma and landed in the World of Build, where he would spend the next two years while searching for Build. From the perspective of the World of Ex-Aid's timeline, Emu's powers and Parado have only been gone for a week, however.
• Unfinished, Untested, Used Anyway: The Kamen Rider Build Gashat is untested and has some side-effects. Namely, the user gets shocked and ends up dropping their transformation after a while. The modified copies Takeru hands to the doctors after Kuroto's initial use of it only mildly improve on this flaw, as he was on a short time limit to fix them and the glitches eventually kick in again.
• Un-person: The ending credits feature a montage of still images from the five previous shows. These stills feature just about every important character from those shows, even if they didn't appear in this movie… with the exception of, in some shots, Fourze's Yuki Jojima, whose absence is even more conspicuous because she was Gentaro's best friend (and still gets name-dropped in this movie).
• Unusual Euphemism: Main!Mogami says the Nebula Gas Enigma uses 'funked up' the Gamer Drivers.
• The Unreveal: Expect to find out how Ankh is restored by the time his future self appears in MegaMax? Too bad; his restoration in this film is temporary. Expect to find out how Gentaro has the Fourze Driver back after its destruction in Ultimatum? Too bad; it appears here without comment. The assistant director admits he had forgotten it was destroyed, and gives it the Hand Wave that this takes place the day before the future portion of Ultimatum.
• Wham Shot: Banjou, upon winding up in the Ex-Aid universe, looks about his new surroundings to find the Skywall completely absent.
• Whatever Happened to the Mouse?: Kamen Rider Brave: ~Let's Survive! Revival of the Beast Riders Squad~ hinted that Foundation X had been looking into the Gashats as a new investment opportunity. Whatever research they were planning on doing for that goes unmentioned in this movie, which focuses instead on the two Mogamis' use of Foundation X's resources for their own plans.
• When the Planets Align: JK figures that the Enigma System in the World of Ex-Aid is at Amanogawa High School for this reason. The school has always been a nexus of Cosmic Energy, and Mogami set Enigma to activate at the moment the planets will align, which would give him incredible power. Sento figures out that activating the Enigma earlier than it is scheduled to will put it out of sync with this alignment and deprive Mogami of his chance to receive the power up he wants.
• Year Inside, Hour Outside: Time flows differently in the two worlds: according to Parado he's been stranded in the World of Build for two years, but according to Emu he only left the World of Ex-Aid a week ago. As the two worlds begin to merge, time normalizes between them in order to avoid any weird complications.