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

This crossovers the Build and Ex-Aid Kamen Rider universes, bringing together heroes from multiple Heisei-era series to stop a scientist named Kaisei Mogami (Kaiser) and Enigma from merging dimensions and destroying humanity. Six Kamen Riders must unite to defend reality against the Nebula Bugster threat.

The story takes place across two intersecting parallel universes, the Build world and the Ex-Aid world. Both dimensions lack the Skywall barrier that previously separated them, allowing Bugsters to spill across realities. The Riders hail from these separate series and must work together despite their different origins.

The film explores three core themes: Dimensional Crossovers (how different Rider worlds collide and their legacies coexist), Teamwork & Unity (heroes learning to cooperate beyond their native technologies), and Power & Identity (how extraordinary abilities can shape or corrupt those who wield them).

Sento Kiryuu is a brilliant scientist-hero who pilots the Build Driver using Doctor and Game Fullbottles. He serves as the team leader, known for decisive action and quick improvisation under pressure. His role is to drive the cross-dimensional charge to stop the Bugsters and prevent Enigma from unraveling reality.

Emu Hojo is a gamer-hero who wields Ex-Aid powers and teams with Build to combat the Bugster outbreak. His tech and gaming instincts prove crucial in unlocking cross-dimension solutions. He navigates the dimensional crisis while preserving friendship and justice values across both universes.

Kaiser is Kaisei Mogami, a breakthrough researcher who develops the Kaiser system and uses Nebula Gas to power his machines. He embodies the dangers of unchecked power, orchestrating a plan to fuse dimensions for control. His antagonistic drive forces the Riders to act decisively to stop Enigma's threat.

Enigma is a central mechanism in the film, connected to the dimensional manipulation that threatens both worlds. It serves as the hub where key confrontations occur and is tied to the Nebula Gas environments. Enigma's lab acts as a critical location for the Riders' investigation into stopping the dimensional convergence.

The events unfold in modern day contemporary settings with a tight 24-hour countdown before the dimensions converge and reality is erased. This urgent timeframe drives the rapid cooperation among Riders from different series and creates constant pacing tension.

Takeru Tenkuuji / Kamen Rider Ghost is a vigilant Rider who steps into the crisis to prevent world destruction. He uses Ghost abilities to confront Nebula Bugsters and acts as a bridge between dimensions, supporting others when their powers falter during the crossover event.

The Riders from Build, Ex-Aid, Ghost, OOO, Fourze, Gaim, and others must combine their powers and strategies despite coming from different series with incompatible technologies. The film emphasizes cooperation over rivalry, with heroes learning to communicate and coordinate across dimensional boundaries to face the existential threat.

The Daitenkū-ji temple is a recurring sanctuary location in the film where characters can return to sanity after experiencing the disorienting effects of dimensional travel and Nebula Gas exposure. It serves as a grounding, safe space amid the chaos of the converging realities.