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

Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders (仮面ライダー平成ジェネレーションズFINAL ビルド＆エグゼイドwithレジェンドライダー) is the Movie War (the ninth overall) crossover between Kamen Rider Build and Kamen Rider Ex-Aid, and the second installment of the Heisei Generations Series. The film premiered in Japanese theaters on December 9, 2017. It was followed by a teaser announcing the then-upcoming Kamen Rider Amazons: The Last Judgement.

The film was released on DVD/Blu-Ray on May 9, 2018.

Synopsis
The story begins following Ex-Aid and Para-DX's battle against Build during Kamen Rider Ex-Aid: True Ending. Build appeared and took Ex-Aid's powers away, but Sento has no recollection of such incident happening other than a dream. Misora has made two new Fullbottles.

When Sento arrived to a Smash distress call, he found a Nebula Bugster instead, the latest mutation of the Bugster Virus. While Sento battled the Nebula Buster, Ryuga was blown into an alternate reality where the Sky Wall never existed, where he meets Emu and the Gamer Riders. The Riders from the world of Build and the Riders from the world of Ex-Aid, alongside the Legend Riders Fourze, OOO, Gaim, and Ghost will stand up against this threat!

Plot
The film begins with Sento Kiryu dreaming about taking Ex-Aid's powers. When he wakes up after Misora finishes purifying the Doctor and Game Fullbottles, he tells the others about his weird dream and reveals his new RabbitTank Sparkling power-up bottle. Then, the team are called into battle when Nebula Bugsters begin attacking Touto. Realizing their powers have no effect on the monsters, Build accesses the Doctor and Game bottles for an Ex-Aid Best Match, then realizing that Ex-Aid was in his dream. Left Kaiser then appears and takes the new bottles from Build and runs off. Cross-Z runs after him and gets sucked into Enigma, a inter-dimensional gateway that brought him to a parallel world where the Sky Wall never existed.

Nebula Bugsters begin to attack the public due to the interdimensional interference caused by Engima, alerting the attention of several former Kamen Riders. The Doctor Gamers arrive to the scene to try to calm the peace, with Emu out of commission due to Build taking his powers the week prior. Right Kaiser then appears and takes responsibility for unleashing the Nebula Bugsters for the sake of empowering the Enigma on his side. He activates the Enigma and sends Build's Earth to their dimension, with the denizens of each Earth in awe after seeing another Earth in the sky. Enigma activates again, this time it renders the Gamer Drivers and Gashats useless. Right Kaizer attacks the Riders, only for them to be protected by the appearance of Kamen Rider Ghost. The Doctor Riders help quell the wounded civilians in medical care while Emu thanks Takeru and Onari for showing up. Then Ryuga appeared and began yelling at Asuna Karino about the Sky Wall. Emu notices the Build Driver on Ryuga and demands for his Ex-Aid powers back, with Ryuga dismissing the idea.

Meanwhile on Build's Earth, Parado has encountered Sento and demands for Emu's powers back, claiming it took him two entire years in an attempt to track Build down. After hearing Parado out, Sento realizes that Parado and "Ex-Aid" came from a world where the Sky Wall never existed. Soichi Isurugi appears and explains that Nebula Bugsters are monsters from a different world infused with their world's Nebula Gas, and the only one who can defeat them are "riders with the power of video games", which he tells Sento that that was the most likely reason as to why Sento refused to return Ex-Aid's bottles. He suggests that Parado use the Game Fullbottle to communicate with Emu on the other side, which succeeded. The conversation confirmed a time difference between the two worlds and that Enigma was able converge the two time zones into one linear flow, and to Sento's acknowledgement that Ryuga was in Ex-Aid's world. The Doctor Riders begin to work a plan out with Kuroto Dan, while Parado falls temporarily ill due to the influence of the Fullbottle over his virus physiology. Soichi continues to explain how Kaisei Mogami once found a way to cross over to parallel worlds using the Sky Wall, and tells Sento to stop him. To help, he leaves behind 2 Full Bottles: Phoenix and Robot.

With a new plan in tow, Kuroto Dan faces the Nebula Bugsters with the new Kamen Rider Build Gashat he created from the data when Build attacked him. The new Gashat would allow him to temporarily conceal the lock embedded onto their gear, albeit only temporary. Kuroto is asked to make more, but he refuses until Onari successfully convinces him to do so.

Sento begins his investigating of Kaisei Mogami by retrieving a profile of him from Gentoku Himuro, to explains that Mogami worked very closely with Takumi Katsuragi. During studies of the Sky Wall, Mogami discovers traces of the Bugster Virus and determined it came from another reality, but the Government refused to fund his development of Enigma: a machine that would allow travel between these two worlds, so Mogami quit and went to work for Nanba Heavy Industries with Katsuragi assisting him in secret whilst maintaining his job for the Government.

Sento then goes through Katsuragis data drive, and finds lots of information: Mogami resalised he could combine the Nebula Gas and Bugster Virus to create the Kaiser System, but in order to do so would need more potent samples of Bugster Virus, so quickly developed the Enigma. Sento realises that the Build that attacked Ex-Aid was actually Katsuragi, but is not sure why he had the dream, assuming it was some sort of reaction to holding the bottle. Confused as to why Katsuragi would take Ex-Aids power, Sento hypothesises that Katsuragi had learned of Mogamis true intent: to combine the worlds of Build and Ex-Aid, the result of which would be the destruction of both worlds.

Sento then starts destoying the Nebula Bugsters, forcing out Left Kaiser. Sento, who has determined at the Nebula Bugsters are the Energy Source for Enigma, was destroying them to shut it down. Left Kaiser then attacks Build, to which Sento uses the two Fullbottles left for him to become Build PhoenixRobo Form, which successfully drives off Left Kaiser. Sento then uses a tracker which he placed on him to track Mogami. On the way, he asks Parado about the 'Muteki' in the Ex-Aid research files, as he is still confused as to why Katsuragi took Emus power rather than Parados. Parado explains that when He and EMu unite, they gain the power of invincibility. Sento realises that the key to defeating Mogami is Ex-Aids Muteki power, which is why he stole Emus power before the Gamer Drivers were disabled by Enigma.

Using Parado as a link, Sento explains to Emu and the others that Mogami is trying to fuse both of their worlds together which will result in their complete destruction. Emu and Ryuga then try to find Enigma in their world, but are stopped by a swarm of Nebula Bugsters. Hiiro, Taiga, Kiriya and Nico are also trying to fight the off in civilian form to little effect when Takeru arrives with 3 Kamen Rider Build Gashats which Hiiro, Taiga and Kiriya use to become Brave, Snipe and Lazer Turbo. Takeru then transforms into Ghost to help.

Emu and Cross-Z are struggling to defeat their Nebula Bugsters which Ryuga confused as to why Emu is fighting so hard despite not being able to transform. An earthquake then opens up a crevase which Ryuga falls in to before being saved by Emu and a mysterious stranger who introduces himself as

Continuity and Placement

 * Kamen Rider Build: Between episodes 14 and 15. The events of this movie happens 2 years after Build's cameo in Kamen Rider Ex-Aid: True Ending in the World of Build's timeline. The ending credits scene with Grease's debut cameo takes place some time after episode 15 when the data to create his Sclash Driver is stolen.
 * Kamen Rider Ex-Aid: 1 week after Build's cameo in Kamen Rider Ex-Aid: True Ending in the World of Ex-Aid's timeline, but before Kamen Rider Ex-Aid "Tricks": Kamen Rider Para-DX.
 * Kamen Rider Ghost: After the events of Kamen Rider Ghost RE:BIRTH: Kamen Rider Specter  but before the events of the Kamen Rider Ghost: Memories of the Future novel.
 * Kamen Rider Gaim: After the events of the previous Heisei Generations movie.
 * Kamen Rider Fourze: After the events of the Kamen Rider Fourze: Ama High Graduation novel but before the events of the Fourze portion of Kamen Rider × Kamen Rider Wizard & Fourze: Movie War Ultimatum.
 * The explanation that Fourze's appearance in this movie occurs before the events of the Fourze portion in Movie War Ultimatum is consistent with this movie's release date in 2017, but contradicts the official statement that Build's cameo in the post-credits scene of True Ending occurs one year after the rest of the movie, as that would set this movie's events in 2018, one year after the destruction of the Fourze Driver in Movie War Ultimatum.
 * Though not likely, the only explanation to this statement is to put this movie in between the day change during the Fourze portion in Movie War Ultimatum.
 * Kamen Rider OOO: After the events of Kamen Rider × Kamen Rider Fourze & OOO: Movie War Mega Max, as well as Eiji's cameo in Kamen Rider × Kamen Rider Wizard & Fourze: Movie War Ultimatum.

Build

 * Misora Isurugi
 * Soichi Isurugi/Evolto
 * Sawa Takigawa
 * Gentoku Himuro

Ex-Aid

 * Parado
 * Asuna Karino
 * Nico Saiba

Others

 * Onari Yamanouchi
 * JK
 * Chuta Ohsugi
 * Hina Izumi (flashback only)
 * Chiyoko Shiraishi (flashback only)
 * Shintaro Goto (flashback only)

Bugster

 * Nebula Bugster

Cast

 * Build cast
 * Sento Kiryu (桐生 戦兎): Atsuhiro Inukai (犬飼 貴丈)
 * Ryuga Banjo (万丈 龍我): Eiji Akaso (赤楚 衛二)
 * Misora Isurugi (石動 美空): Kaho Takada (高田 夏帆)
 * Sawa Takigawa (滝川 紗羽): Yukari Taki (滝 裕可里)
 * Takumi Katsuragi (葛城 巧): Yukiaki Kiyama (木山廉彬)
 * Gentoku Himuro (氷室 幻徳): Kensei Mikami (水上 剣星)
 * Soichi Isurugi (石動 惣一): Yasuyuki Maekawa (前川 泰之)
 * Ex-Aid cast
 * Emu Hojo (宝生 永夢): Hiroki Iijima (飯島 寛騎)
 * Hiiro Kagami (鏡 飛彩): Toshiki Seto (瀬戸 利樹)
 * Taiga Hanaya (花家 大我): Ukyo Matsumoto (松本 享恭)
 * Kuroto Dan (檀 黎斗): Tetsuya Iwanaga (岩永 徹也)
 * Asuna Karino (仮野 明日那): Ruka Matsuda (松田 るか)
 * Kiriya Kujo (九条 貴利矢): Hayato Onozuka (小野塚 勇人)
 * Parado (パラド): Shouma Kai (甲斐 翔真)
 * Nico Saiba (西馬 ニコ): Reina Kurosaki (黒崎 レイナ)
 * Returning cast
 * Eiji Hino (火野 映司): Shu Watanabe (渡部 秀)
 * Ankh (アンク): Ryosuke Miura (三浦 涼介)
 * Gentaro Kisaragi (如月 弦太朗): Sota Fukushi (福士 蒼汰)
 * JK (ジェイク): Shion Tsuchiya (土屋 シオン)
 * Chuta Ohsugi (大杉 忠太): Takushi Tanaka (田中 卓志)
 * Kouta Kazuraba (葛葉 紘汰): Gaku Sano (佐野 岳)
 * Takeru Tenkuji (天空寺 タケル): Shun Nishime (西銘 駿)
 * Onari Yamanouchi (山ノ内 御成): Takayuki Yanagi (柳 喬之)
 * Musashi Damashii, Nobunaga Damashii, Grimm Damashii (ムサシ魂, ノブナガ魂, グリム魂): Tomokazu Seki (関 智一)
 * Guest Cast
 * Kaisei Mogami (最上魁星): Kenji Ohtsuki (大槻 ケンヂ)

Uncredited

 * Kamen Rider Grease (仮面ライダーグリス): Kouhei Takeda (武田 航平)

Suit Actors

 * Kamen Rider Build, Kamen Rider OOO, Kamen Rider Fourze, Kamen Rider Gaim: Seiji Takaiwa (高岩 成二)
 * Kamen Rider Ex-Aid: Yuji Nakata (中田 裕士)
 * Kamen Rider Cross-Z: Eitoku (永徳)
 * Kamen Rider Grease: Satoshi Fujita (藤田 慧)

Fullbottles

 * Bottle Used:
 * Build
 * Sento
 * Organic: Rabbit, Doctor, Kaizoku, Lion (in Build Phone), Taka, Ninjya, Phoenix
 * Inorganic: Tank, Game, Densha, Gatling, Comic, Robot
 * Other: RabbitTank Sparkling
 * Takumi (Flashback)
 * Organic: Rabbit, Gorilla
 * Inorganic: Tank, Diamond
 * Cross-Z
 * Dragon
 * Form Used:
 * Build
 * RabbitTank Form, Ex-Aid Form, KaizokuRessya Form, HawkGatling Form, NinninComic Form, PhoenixRobo Form, RabbitTank Sparkling Form

Rider Gashat

 * Gashat Used:
 * Ex-Aid
 * Mighty Action X, Maximum Mighty X, Hyper Muteki, Bakusou Bike (in Kimewaza Slot Holder), Kamen Rider Build (in Gashacon Breaker)
 * Brave
 * Taddle Legacy, Taddle Quest, Kamen Rider Build
 * Snipe
 * Gashat Gear Dual β (Bang Bang Simulations), Bang Bang Shooting, Kamen Rider Build
 * Lazer (Turbo)
 * Bakusou Bike, Kamen Rider Build
 * Genm
 * Gamer Driver
 * Dangerous Zombie, Kamen Rider Build
 * Level Used:
 * Ex-Aid
 * Action Gamer Level 2, Muteki Gamer
 * Brave
 * Legacy Gamer Level 100, Quest Gamer Level 2
 * Snipe
 * Simulation Gamer Level 50, Shooting Gamer Level 2
 * Lazer (Turbo)
 * Bike Gamer Level 2, Bike Gamer Level 0
 * Genm
 * Zombie Action Gamer Level X-0

Ghost Eyecons

 * Eyecon Used:
 * Ore, Newton, Eyecon Driver G, Mugen
 * Damashii Used:
 * Ore Damashii, Newton Damashii, Grateful Damashii, Mugen Damashii
 * Ghosts summoned through Eyecon Driver G:
 * Musashi, Nobunaga, Grimm

Lockseeds

 * Lock Used:
 * Orange, Sakura Hurricane, Kachidoki, Kiwami
 * Arms Changes
 * Orange Arms, Kachidoki Arms, Kiwami Arms
 * Lock Vehicle:
 * Sakura Hurricane

Astroswitches

 * Switches Used:
 * Circle - Rocket, Chain Array, Cosmic
 * Cross - Giantfoot, Launcher
 * Triangle - Gatling, Drill
 * Square - N/A
 * States Used:
 * Base States, Cosmic States

Core Medals

 * Medals Used:
 * Head - Taka, Kuwagata
 * Arms - Tora, Kamakiri, Kujaku
 * Legs - Batta, Condor
 * Combos Used:
 * Tatoba Combo, Gatakiriba Combo, Tajadol Combo

Theme song

 * Kamen Rider Heisei Generations FINAL Special Medley

International Movie Theaters
The film was released in Taiwan in February 2018, and Hong Kong in March 2018, available in both Japanese language with Chinese subtitles and Chinese dub.

Errors

 * The placement of the two parallel Earths next to each other is inconsistent throughout the entirety of the film. Whilst the characters from their respective worlds are able to see the counterpart world's Japan directly above them, the zoomed out shot of both Earths instead has both Japans facing outward instead of facing each other.
 * When the camera pans out for JK to take a picture of the Doctor Riders, Ghost is mysteriously out of the shot despite standing in front of the Riders.
 * When the Doctor Riders activate Kamen Rider Build Gashats to transform, they don't wear a Gamer Driver, but it suddenly appears in the very next scene.
 * When Emu transforms and the profile array appears, two silhouettes are seen in place of Ex-Aid's Double Action Gamer Level X and Genm's Action Gamer Level 1, even though they aren't seen when the other Doctor Rider transform.
 * When Emu transforms along with Sento, Bike Gamer is also materialized, even though he didn't activate a Bakusou Bike Gashat.
 * Before Takeru transforms into Ghost, he is not seen summoning the Ghost Driver and it just appears on him even though it wasn't there in the previous scene.
 * On one scene, the Build suit is actually reversed while Ex-Aid Muteki Gamer is fighting Bikaiser.
 * Fourze using a Module that is on his right arm in Cosmic States is impossible as it would revert him back to Base States.
 * When OOO changes into Tajadol Combo as well as the majority of OOO's Combo Changes, the sound effects for inserting the medals and scanning them are from the Medajalibur and Birth Driver.
 * However, the Foundation X Medals released in the Complete Selection Modification OOO Driver Complete Set reveal that the medals are programmed to emit Cell Medal sounds, so this may not be an error.
 * Around the time that Build transforms into RabbitTank Sparkling, the gear color of Bikaiser are reversed.
 * When Ex-Aid transforms into Muteki Gamer, the Hyper Muteki projection screen isn't seen.
 * When Snipe changes into Simulation Gamer, the sound announced is different than the original one, much like when Para-DX assumes his Level 50 forms.
 * When Eiji, Emu, and Ryuga confront Kaisei Mogami in his lair, he states that Eiji cannot transform. Later, Ankh is shown pilfering Foundation X's Core Medals from the Greeeds and giving them to Eiji, implying that the reason Eiji could not transform is because he lost his Core Medals at the end of OOO. This seems to be ignoring the fact that Eiji regained the Core Medals in Movie War Mega Max and has used them to transform in subsequent appearances.
 * Before OOO performs Prominence Drop, for unknown reason his adjusted the OOO Driver.
 * When Sento transforms with Emu, after the Driver announces "Best Match", Sento just leaves his hand around the lever without cranking it for no apparent reason.