"You fools could never hope to defeat me. Do you know why? Because I was born to be king!"

Kamen Rider Ohma Zi-O (仮面ライダーオーマジオウ, Kamen Raidā Ōma Jiō), or simply Ohma Zi-O, is the final form of Sougo in a dystopian future. His visor reads "Rider" (ライダー, Raidā), while the logo on his forehead reads "Kamen" (カメン, "Kamen") in katakana. In the initial position of the timeline, Sougo obtained this form on the event of Oma's Day, gaining control over the Dai Mazines and obtaining power of all Heisei Kamen Riders known to exist till date.[4]
Compared to all of the other forms of Zi-O, Ohma Zi-O's skills are far beyond anything seen so far in the series. In addition to that, though Zi-O (2018-19), Geiz, and Woz need to use Ridewatches in their Drivers and/or weapons for using Legend/Future Rider powers, Ohma Zi-O can simply use them either through his will or by activating the respective Ridewatches.

Sougo Tokiwa (常磐ソウゴ, Tokiwa Sōgo) is the ruler of 2068 who transforms into Kamen Rider Ohma Zi-O (仮面ライダーオーマジオウ, Kamen Raidā Ōma Jiō).

This iteration of Sougo Tokiwa followed the events of his main counterpart, up until the arrival of Geiz, Woz and Tsukuyomi from the future. On September 8th, 2018, he eventually obtained his Ziku-Driver and the Zi-O Ridewatch to become Kamen Rider Zi-O. Unlike the main Sougo, Ohma Zi-O did not at any point become discouraged, thus it did not create a path for GeizRevive's existence.

Eventually, Sougo Tokiwa obtained the Zi-O Ridewatch II and gained additional abilities to manipulate time however he wanted to. On April 7, 2019, Sougo evolved into Kamen Rider Ohma Zi-O from his base form during the events of Oma's Day. Using this newfound power, he destroyed the world using the Dai Mazines, eventually wiping out at least 50% of the Earth's population, and began his rule over the planet.

During one of Resistance's battles against the tyrant, Ohma Zi-O stood behind his monument as he effortlessly wipes out the army. He declares that none of them were capable of defeating him because he was "born to be king". Sometime after this ordeal, Geiz Myokoin and Tsukuyomi traveled to the past, with the intent on guiding Sougo Tokiwa's fate of becoming Ohma Zi-O. Knowing this would jeopardize his own existence, Ohma Zi-O sent Woz after them.

One day, as he perched on his chrysanthemum throne in an isolated field, Ohma Zi-O sensed his past self's presence in 2068 after being sent there by Tsukasa Kadoya. He summoned Dragreder to bring both his past self and Tsukuyomi to him. Ohma Zi-O met the past Sougo and acknowledged their dreams that destined them to become king. Despite his past self's protests, Ohma Zi-O claimed he accomplished their dream into becoming the "greatest and kindest Demon King", enraging the past Zi-O to engage the tyrant but failed due to Ohma Zi-O's overwhelming strength and experience with the Ridewatches. After the battle, he suggests to the past Sougo to give up the Ziku-Driver and sends him and Tsukuyomi back to 2018, knowing that he'll be erased from the timeline. He was restored back to existence knowing his past self couldn't give up his dream.

After the past Sougo acquired the power of Zi-OTrinity and the Blade Ridewatch, Daiki Kaito presented Sougo and Geiz with a message from Ohma Zi-O, who congratulated his past self for having collected the Blade Ridewatch, having known about it all along. Ohma Zi-O then manifested six Ridewatches: Agito, Hibiki, Kabuto, Den-O, Kiva, and Drive, and told the past Sougo that he would have to obtain kingship by acquiring the remaining six Rider powers

After his past self obtained all the Ridewatches, Ohma Zi-O transported GrandZi-O back to 2068 to congratulate his past self for his newfound power, but claimed he's still no match for him. While he fought GrandZi-O using the powers of the various Kamen Riders, Ohma Zi-O had the upperhand once Kamen Rider Drive was summoned. Ohma Zi-O took hold of the manifestation and allowed Drive to defeat GrandZi-O. Despite his past self obtaining nineteen Ridewatches, he didn't obtain the Drive Watch properly as that was previously Ohma Zi-O's. After Woz wisked Sougo away to safety, Ohma Zi-O commended his servant but began to notice someone in the past had altered the timeline, placing his current one in jeopardy. Eventually, his past self was able to return the timeline back to normal, and Ohma Zi-O's existence was untouched.

Once Swartz surfaced as Another Decade and waged a war threatening the Kamen Riders' timelines, the past Sougo arrived to meet Ohma Zi-O during the Resistance's raid. While he did not expect his past self returning to 2068 again, the past Zi-O assured history has changed and was Ohma Zi-O's past was his future. Through the teamwork with his comrades, the past Zi-O briefly overwhelmed Ohma Zi-O. Remarking how much the past Sougo would do anything to sacrifice himself for his comrades, Ohma Zi-O reveals to the past Sougo that his power is to destroy space and time itself, a power Swartz can never imagine. The future Sougo wishes to see the present Sougo's next move, as he sends Sougo back to his timeline. Aware that his past self is trying to turn Tsukuyomi into a Kamen Rider, he empowers the blank Ridewatch in Tsukuyomi's pocket.

After his past self became Kamen Rider Ohma Zi-O and defeated Swartz, Ohma Zi-O learned that the past Sougo's intentions to erase the current timeline. Ohma Zi-O had one final conversation with his younger self if he is making the right choice. He listened on how the past Sougo, while having accomplished his goal of becoming a king, cannot reign supreme without his friends. With Ohma Zi-O's blessing, the past Sougo used power as the King of Time to recreate the world's history. Ohma Zi-O bid farewell to his past Sougo before being erased from the timeline, as he admitted that it was interesting to have met his young counterpart

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