Kamen Rider: Reiwa The First Generation is the eleventh annual Kamen Rider Movie War crossover film and the first of the Reiwa era, serving as a crossover between Kamen Rider Zi-O and Kamen Rider Zero-One. It was released on December 21, 2019.
The Hiden Zero-One Driver can only be used by the company's president. Whose will was the one that led to the creation of this device and it falling in the hands of Aruto Hiden? Kamen Rider Zero-One's birth story will be revealed!
Kamen Rider Zi-O, who fought as the greatest Demon King of Heisei Kamen Riders chose to reset the world and live a new life. Why does Sougo Tokiwa transform into a Kamen Rider again and meet Zero-One? Kamen Rider Zi-O's true ending chosen by Sougo will be revealed!
The world of Kamen Rider Zero-One and the world of Kamen Rider Zi-O. The two heroes live in different worlds, but what is waiting for them after crossing time and space into a single world? Union or conflict? This winter marks a new legend in the history of Kamen Rider.
Tropes that appear in this work:
- Big-Bad Ensemble: The Big Bad role of this film is split between the Time Jacker Finis who created the Zero-One Anotherwatch and later on becomes Another 1, complete with a more powerful form after absorbing Geiz's Time Mazine and Will/Another Zero-One.
- Clipped-Wing Angel: Kamen Rider 001 is a kitbashed emergency form that's used only because Zero-One's regular powerset isn't available. The transformation itself is visibly agonizing, and 001 lacks Zero-One's array of tools and more powerful forms.
- Demoted to Dragon: Due to alterations to the timeline Horobi and Jin, originally the leaders of MetsubouJinrai.NET, appear as members of Will's HumaGear uprising.
- Early-Bird Cameo: The Stinger shows the first appearance of Kamen Rider Thosuer.
- FaceHeel Turn: Soreo Hiden, originally Aruto's HumaGear Parental Substitute who died protecting him, is a member of Will's HumaGear uprising in this timeline and fights Aruto as Kamen Rider Ichi-Gata. In truth, he's secretly protects humanity, including his son, such as such as secretly giving him a MetsubouJinrai Force Riser as a temporary transformation device until he regains his powers as Zero-One.
- Loophole Abuse: Another Zero-One's alteration of history prevents Aruto from transforming using his real Driver, but the Force Riser that existed before the point when history was altered isn't affected. Plus, it allows him to become what basically and technically is a different Rider. As in, he just lost his Zero-One power, but nothing stops him from becoming 001 instead.
- Original Generation: While Will's backstory is rooted in Zero-One's world and lore, Finis has no apparent connection to the Time Jackers of Zi-O beyond using the same title, much like Tid from Heisei Generations FOREVER.
- Painful Transformation: The transformation into 001 is very painful, and Aruto screams and contorts in agony as he changes into this form.
- Robot War: Will instigated one after seizing control of Hiden Intelligence, leading the HumaGears to attack humans.
- Set Right What Once Went Wrong/Make Wrong What Once Went Right: Finiss actions prevented the Daybreak Incident from happening, but they also led to Korenosuke Hiden dying several years earlier than he did in the original timeline and his HumaGear secretary taking power and waging a Robot War.