Kamen Rider Zi-O is the twentieth and final Kamen Rider series in the Heisei Era, produced by Toei. The series is led by a plucky high school graduate, Tokiwa Sougo, in his quest to become a king. He is joined by his herald, Woz, Myokoin Geiz as the deuteragonist, Kamen Rider Geiz, and Tsukuyomi in a bid to prevent the glum, apocalyptic future from happening by the Timejackers bent on making their own “king of time” through the creation of Another Riders.
WARNING: THIS POST CONTAINS SPOILERS!
The article below covers Kamen Rider Zi-O episodes 29-30, and Rider Time: Kamen Rider Ryuki three episode mini-series. If you have yet to watch these, avert your eyes now.
Currently running at 32 episodes (at the time of writing), the series has been responsible for changing or rewriting the canon of the previous Heisei Rider series. Most recently, Zi-O’s escapades have drastically affected the canon for Kamen Rider Blade and Kamen Rider Ryuki.
Kamen Rider Blade
Episodes 29 and 30 focused on Kamen Rider Blade’s arc. Out of spite from losing his savior, White Woz seeks out Kurihara Amane, still working in Jacaranda, and forcing the Another Blade Ridewatch on her. Going berserk as Another Blade eventually forced Aikawa Hajime to come out of hiding, which also prompted Kazuma Kenzaki to reappear, resuming the Battle Fight they vowed to avoid 14 years ago. Although their battle was temporarily halted due to Amane returning back to normal, White Woz’s continued interference has made Blade and Chalice battle against Another Blade once more.
This is where Kamen Rider Blade updates its canon ending. With Blade and Chalice down, Another Blade seals the two Joker Undead essences in its armor, effectively turning Kenzaki and Hajime back to human. Another Blade, now technically the remaining Human Undead, summons the Monolith filled with Darkroaches ready to annihilate all life on Earth as it was destined to be. Kamen Rider Zi-O, with his new Trinity Form, eventually defeats Another Blade, banishes the Monolith, and seals Blade and Chalice’s powers in Ridewatches. With their powers sealed and their bodies returned back to human, Kenzaki and Hajime’s ending is now assumed to be free from the shackles of the Battle Fight.
Kamen Rider Ryuki
Changes to Ryuki’s canon does not overtly happen during the main Zi-O series. Rather, the changes in canon happen in the Rider Time spinoff of Kamen Rider Ryuki, a three-episode mini series. Rider Time: Kamen Rider Ryuki happens 16 years after the ending of the main Ryuki series. A mysterious woman has restarted the Rider Battle, sending all the Riders of the series back in the Mirror World.
In this new spinoff, all the Riders thrust into the Mirror World Rider Battle once again are left with no memories, except for their names and their respective Advent Decks. The mysterious woman, Sara, however, will not grant a wish to the victor unlike the previous series. This new Rider Battle makes all the Riders hostage in a battle royale to the death until a sole survivor is left. Sara will then grant the winner his life back in the real world.
The first two episodes fill up most of the Rider Battles. It also gives all the characters clarity regarding their identities, especially that of Shinji Kido (Ryuki) and Akiyama Ren (Knight), as revealed by Asakura Takeshi (Ouja) who somehow inexplicably retains his memories of the previous Rider Battle. Dark Shinji also takes a part of the spotlight by taking over Kido’s personality in a bet to win the Rider Battle and escape Mirror World for good.
Without diving into more details and how Zi-O indirectly plays into the plot, the spinoff turns the Ryuki ending into a tragic one. Ryuki’s original ending has everyone return to their old lives prior to the Rider Battles thanks to Ren’s wish. Unfortunately, the wish was for naught as all of the Riders, save for Kido, perished in this restarted Rider Battle once more. Kido, as the remaining survivor, is left without his best friend, and the burden of having the memories from both Rider Battles. It can also be safely assumed that Shiro Kanzaki, taking the mantle of Kamen Rider Odin, also perished after having been defeated by Zi-O and Geiz. His identity is somehow confirmed after whispering “Yui…,” his sister’s name, before disintegrating.
These Riders are not the only series in the Heisei Rider era that have their canonical post-series stories changed due to Zi-O’s interference. Examples of these include Kamen Rider Gaim’s God of Helheim/The Beginning Man/Kazuraba Kouta vanishing from existence and Kumon Kaito being alive again; Hino Eiji and Izumi Hina losing their memories from the events of Kamen Rider OOO; and Kamen Rider Faiz’s Takumi Inui and Masato Kusaka having averted their deaths from the Kamen Rider Yongou web mini-series and Kamen Rider Faiz respectively.
With Kamen Rider Zi-O still having to collect six remaining Ridewatches, it’s a mystery how the series will drastically affect the canon of the Kamen Riders they have yet to meet.