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

• Author's Saving Throw: Word of God admits to have missed out that the Fourze Driver was destroyed in Kamen Rider × Kamen Rider Wizard & Fourze: Movie War Ultimatum, so he declared chronologically that this movie takes place before Fourze's section.
• Role Reprise: For the first time ever in a crossover involving more than two seasons, all of the returning characters are portrayed by their original actors. Most noteworthy is Gaku Sano as Kouta Kazuraba, because Gaim's appearance in the previous Heisei Generations movie was a Fake Shemp deal that reused Sano's audio clips from previous movies and episodes.
• Stunt Casting: Possibly in the case of Sota Fukushi, Kamen Rider Fourze, appearing in Heisei Generations FINAL after his agency kept him away from the franchise for about five years. Then you learn that he’s got a major motion picture coming soon, the Live-Action Adaptation of Bleach, and it makes a little more sense.
• What Could Have Been: According to an interview for Toei Hero Max Vol. 57 with producer Takahito Ōmori, and a dialogue between Ex-Aid head writer Yuya Takahashi and Build head writer Shōgo Mutō in the movie pamphlet:
  • It was initially planned for Takahashi to write most of the movie alone while Mutō was still focused on the early writing and planning of the Build series. The writing process ended up being Mutō putting together a simple draft without a plot, Takahashi writing an Ex-Aid-centric plot based on that draft, Mutō adding on elements of Build to Takahashi’s draft, and the two of them making corrections and additions as they passed the screenplay back and forth to each other.
  • The story was originally going to have more focus on Sento’s Identity Amnesia. While the amnesia plot point does get brought up and has relevance to the final product, it was ultimately decided to devote more attention to Cross-Z learning what makes A True Hero from the Legend Riders he would encounter.
  • Kaisei Mogami was going to have the same personality across both versions. After Kenji Ōtsuki was cast, he and director Kazuya Kamihoriuchi decided to give the two iterations of Mogami a Red Oni, Blue Oni dynamic to help the viewer distinguish them from one another, leading to the World of Ex-Aid’s Kaisei Mogami having an Evil Is Hammy demeanor.

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