Stop hand


This Article Contains Spoilers - WARNING: This article contains major spoilers. If you do not wish to know vital information on plot / character elements in a story, you may not wish to read beyond this warning: We hold no responsibility for any negative effects these facts may have on your enjoyment of said media should you continue. That is all.

You fools could never defeat me. And do you know why? Because I was born to be king!
~ Oma Zi-O boasting about himself.

Oma Zi-O, born Sougo Tokiwa, also known as the Demon King and formerly known as Kamen Rider Zi-O, is the titular central antagonist of Kamen Rider Zi-O. He is the future self of the series' protagonist, Sougo Tokiwa, who achieved a nigh-omnipotent status in the future and rules the Earth in the year 2068 as its king.

He is the reason that most of characters travel back in time, either in order to stop him by eliminating Zi-O or preventing Sougo from becoming Zi-O, like Geiz, Tsukuyomi and White Woz, or coronating a person other than Sougo to be Oma Zi-O, like the Time Jackers.

He was voiced by Rikiya Koyama, who also played Kagetane Hiruko, Giovanni in Pokémon Origins, Kiritsugu Emiya, Kamen Rider Bujin Gaim in Kamen Rider × Kamen Rider Gaim & Wizard: The Fateful Sengoku Movie Battle and Paradox Roidmude in Kamen Rider Drive: Surprise Future.



When Sougo was young he was abducted along with several other children on a bus trip and had Sworz whisper in his ear that he would one day become king.

2018 - 2068

On a day known as the "Day of Oma", Oma Zi-O conquered the world with seven machines called Dai Mazines, using his vast powers and time manipulation to wipe out half of humanity and subjugate the rest. A resistance soon arose to oppose him, but Oma Zi-O easily suppressed them. In the first episode, he is seen using his powers to fight them off before boasting of the fact that he was "born to be king". Unable to defeat Oma Zi-O in the future, two members of the Resistance, Tsukuyomi and Geiz, traveled to the past to change the future by changing his past self's fate of becoming Oma Zi-O.

After Sougo Tokiwa was flung into the future by Kamen Rider Decade, Oma Zi-O had Dragreder bring his past self and Tsukuyomi to him. The Demon King reveals himself as Sougo's future self, shocking the past Sougo. Deducing that his past self was in denial about becoming the Demon King, the future Sougo tells his past self that it's their destiny to become king and "save" the world. Angered, the past Sougo transforms into Kamen Rider Zi-O and attempts to attack his future self, but the future Sougo transforms into his Kamen Rider form as well and beats him down. As Oma Zi-O continues to pummel Zi-O he offers his past self a choice, telling him that if he doesn't want to become the Demon King then all he needs to do is destroy his Ziku-Driver.

Soon after Oma Zi-O launched an attack that forced Sougo out of his transformation. Oma Zi-O then opens a window in time to display his servant Kasshin beating down Kamen Rider Geiz Faiz Armor. Oma Zi-O tells his past self to return to 2018 and creates a time portal to allow the past Sougo and Tsukuyomi to travel through back to their time.

Future Sougo then reverts his transformation and takes a seat on his throne. In 2018, Sougo allowed Geiz to destroy his Ziku-Driver causing Oma Zi-O to be erased from the timeline. However, Sougo would later become Kamen Rider Zi-O again, and as a result his future was restored as well. As he's returned to existence, the future Sougo let out a laugh, revealing he knew what decision his past self would make.

Once Sougo acquired the Trinity and Blade Ridewatch, Oma Zi-O had Daiki Kaito deliver a message from himself to his past self where he congratulated past Sougo for obtaining the Blade Ridewatch, before manifesting the six remaining Ridewatches and telling his past self that once he collects the powers of the six remaining Kamen Riders he will become king.

After present Sougo achieved the power of GrandZi-O from obtaining the power of the past 20 Riders, he traveled to 2068 to face Oma Zi-O again. However, Zi-O found he could not match up to his future self as he still had yet to obtain one Rider power, the power of Kamen Rider Drive, which had instead been stolen from Oma Zi-O by Geiz. When Zi-O summoned Drive Oma Zi-O turned him against Sougo and used him to force Sougo out of his transformation. Though untransformed, Sougo got up and attempted to face off against his future self again. Oma Zi-O then unleashed a flurry of explosions against his past self, before Woz swept Sougo up in his scarf and sent him back to 2019. As Woz bowed before his Demon King, Oma Zi-O realized that someone had changed the flow of time, resulting in a future where Hiryu Kakogawa became Oma Zi-O. This timeline was averted when Sougo Tokiwa as Grand Zi-O defeated Hiryu as Another Zi-O II, restoring history to normal.

Kamen Rider Zi-O: Over Quartzer

As Sougo is confronting Kamen Rider Barlckxs, Oma Zi-O appears to his past self to give him a speech inspiring him to not give up before delivering the Oma Zi-O Ridewatch to him.



  • His name can alternatively be spelled as "Ohma Zi-O" with the first word being an anagram for "Maoh" which in Japanese means "Demon King".
  • Befitting the series' motif as a summarization for the entire Heisei Kamen Rider continuity for the past 19 years, Oma Zi-O shows resemblence and similarities to other previous Heisei Kamen Rider villains, on characteristics and physical appearance, including:
    • Oma Zi-O shares similar name to Prime Minister Orma / Kamen Rider Sorcerer, and they both have the color gold as their color theme.
    • Oma Zi-O is a villainous rider connected to time and/or time-travel, just like Kamen Rider Bujin Gaim and Kamen Rider Dark Drive. All three are also evil counterparts from another era to the heroic Riders, although Bujin Gaim is from the past, while both Dark Drive and Oma Zi-O are from future. In addition, they all share the same voice actor.
    • His red eyes and golden Rider armor bears chromatic resemblence on Tenjuro Banno as Gold Drive and Masamune Dan as Gamedeus Cronus.
    • Like Bat Fangire (as the original Kamen Rider Dark Kiva) from Kamen Rider Kiva, Oma Zi-O is the evil counterpart to a heroic character with the same Rider Armor (P.S. Taiga Nobori became Dark Kiva in the finale of Kiva). However, Oma Zi-O is the future evil counterpart of Sougo himself, while King is both the father and past predecessor to Taiga. They also both have "King" in their title.
  • Curiously, Oma Zi-O's "eyes" resemble to shape of an eagle, possibly hinting at a connection to Shocker. The logo of Zi-O, which is depicted on Oma Zi-O's forehead, also shows an "X"-like symbol, which could perhaps hint at a connection to Foundation X as well.


           Zi-O Logo Villains

Time Jackers
Uhr | Ora | Swartz | Tid

Another Riders
Another Build | Another Ex-Aid | Another Fourze | Another Faiz | Another Wizard | Another OOO | Another Double | Another Den-O | Another Kuuga | Another Gaim | Another Ghost | Another Shinobi | Another Quiz | Another Ryuga | Another Kikai | Another Zi-O | Another Blade | Another Agito | Another Ryuki | Another Hibiki | Another Kiva | Another Kabuto | Another Den-O II | Another Drive | Another Decade

Oma Zi-O's Forces
Oma Zi-O | Woz | Kasshin | Dai Mazines

Future Riders
White Woz | Kamen Rider Ginga

Legendary Riders
Masato Kusaka | Kaito Kumon | Tsukasa Kadoya | Hajime Aikawa | Daiki Kaito | Shun Kageyama (Imposter) | Katsumi Daido

A.R. World Riders
Kamen Rider G4 | Kamen Rider Fuma | Kamen Rider Dark Ghost | Kamen Rider Rey | Kamen Rider Eternal | Kamen Rider Woz | Kamen Rider Yuuki

Kamen Rider Barlckxs | Kagen | Jogen | Woz | Kasshin

Past Villains
Salis Worms | Gryllus Worm | Mole Imagin | Masquerade Dopants | Waste Yummies | Stardust Ninja Dustards | Elementary Inves | Ghouls | Elementary Inves | Low-Class Roidmudes | Chase | Gamma Commandos | Guardians | Hard Guardians | Strong Smash Hazard


Rider Time Shinobi
Niji no Hebi
Yaminin | Stardust Ninja Dustards

Rider Time Ryuki
Tatsuya Kano | Takeshi Asakura | Jun Shibaura | Ishihashi | Tozuka | Kamen Rider Odin

Community content is available under CC-BY-SA unless otherwise noted.