Sougo Tokiwa

Sougo Tokiwa (常磐ソウゴ) is a 18-year-old high school student who dreams of becoming a king one day. Later, Sougo uses the Ridewatches and the Ziku-Driver to transform into Kamen Rider Zi-O (仮面ライダージオウ).

He learns of a tyrannical ruler in the future named Oma Zi-O who is said to be Sougo himself. With that, he makes it his goal to be a great king through kindness to save humanity. He is being attacked by another Kamen Rider from the future bent on killing him to change the course of history.

History
Sougo Tokiwa was born on April 28, 2000. Living with his grand-uncle Junichiro in a clock shop, he attended high school at Hikarigamori High School, excelling in history but poor in physics. From an early age, Sougo believed that he would become a king, much to the consternation of his uncle.

The Birth of Zi-O
One day, Sougo found a mysterious watch-like item that was on the seat of his bicycle, and after examining the blank item, Sougo laid down the blank item, then went on home while minding his own. Later while bicycling down a small street up towards a stairway, a man in hood, holding a grimoire appeared out of nowhere, who told him that it would be a momentous day for him and to avoid the "red robot" before mysteriously disappearing.

He does indeed encounter the robot shortly after, run by a man in red and black attire and attacks Sougo. He is saved by a woman claiming to be from the future named Tsukuyomi in her Time Mazine. They seemingly travel back in time to 1671 Japan where she proves her legitimacy to him. Tsukuyomi warns Sougo that the watch he currently had possessed a tremendous amount of power and using it will make Sougo turn into the worst and lowest overlord, Oma Zi-O. Just before Sougo could reply, a fight occurs and Tsukuyomi decide to test whether Sougo is really Oma Zi-O or not by forcefully putting Sougo in the middle of the fight. The citizens proceed to throw Sougo to a river and doing so makes peace for themselves. Instead of lamenting his misfortune, Sougo is relieved to see that the group had reconciled, much to the citizens’ amusement. However, a red Kamen Rider, Geiz manages to tail them and the two retreat back into the Time Mazine.

When Tsukuyomi was being attacked by Geiz, Sougo gets kicked out of the mech and wakes up in a strange world with a huge wall in the horizon. As he ponders over this, a Smash attacked him but luckily Kamen Riders Build and Cross-Z appears to help. After revealing their names, Sento and Ryuga bring Sougo to the cafe Nascita.

As Ryuga drinks from a carton of milk, Sougo sees the expiration date and realized that he's indeed in the year 2017. Sento affirms that Sougo is indeed from the future since, after some analysis, Sougo's Ridewatch is different from any current technology. Before Sento can ask about the future, Tsukuyomi appeared and shot the three of them into unconsciousness using Faiz Phone X, in order to prevent Sougo from interfering with the past any more than necessary. He wakes up in his old home, believing it to be all a dream. Later, he encounters a monster with the similar look of Kamen Rider Build attacking civilians. He tries to stop him but is quickly subdued twice.

Sougo was approached by the prophet, Woz once again, who then tells him that he'll become an overlord who will reign over the future. Tsukuyomi desperately tries to warns Sougo to not use the Ridewatch. However, after some quick thought, Sougo decided to not become a tyrant, but to become a beloved overlord of the future, much to both Tsukuyomi and Woz’s surprise. After that, the blank Ridewatch revealed itself to becoming the Zi-O Ridewatch, then Sougo is given the Ziku-Driver by Woz to transform and battle the elusive Kaijin Rider. As it is his new beginning of becoming a Kamen Rider, Woz announced the introduction of Sougo as he was now Kamen Rider Zi-O, the King of Time, much to Tsukuyomi’s disappointment.

He is able to go on par with Another Build and is quick to defeat him using the Zikan GiLade finisher. Geiz enters the fray, seemingly frustrated with Sougo on his decision and Tsukuyomi as she failed in convincing him. Geiz proceeds to ask why Sougo became Zi-O, which the latter replied that it was probably decided from the moment he was born. Reminiscing Oma Zi-O’sdeclaration, Geiz deems Sougo as irredeemable and transforms using both Geiz and Ghost Ridewatchs to become Kamen Rider Geiz Ghost Armor and advances towards Zi-O.

Obtaining the power of Build
Later, Sougo went to the same cafe to meet Sento and Ryuga again. Sento said to Sougo to take care of his past self and gives him the Build and Cross-Z Ridewatches.

Personality
Sougo is described as an ambitious young man who desires to be a king. However, upon learning of his future self being a tyrant, he decides to change his fate. The current reason is yet to be known of why he is like that except the fact that Sougo somehow felt that it is his fate.

Despite his grand ambitions, Sougo is a peaceful and genuinely kind man at heart, and will gladly take physical harm if it means stopping a conflict, much to Tsukuyomi’s confusion.

Abilities

 * Vast Historical Knowledge: According to Tsukuyomi, Sougo excels in history.

Forms
Kamen Rider Zi-O transforms by inserting the Zi-O Ridewatch into the right-hand side of the Ziku-Driver and rotating the Driver 360 degrees. He accesses Armor (アーマー) forms based on previous Heisei Kamen Riders by inserting Ridewatches into the left-hand side of the Ziku-Driver.

Devices

 * Ziku-Driver - Transformation device
 * Ridewatches - Transformation trinkets

Weapons
Handheld weapons:
 * Zikan Girade - Zi-O's personal weapon
 * Ride HeiSaber - Zi-O's personal weapon while using Decade Armor

Suit-equipped weapons:
 * Drill Crusher Crusher - Zi-O Build Armor's personal weapon based on the Drill Crusher.
 * Gashacon Breaker - Zi-O Ex-Aid Armor's personal weapon

Vehicles

 * Ride Striker
 * Time Mazine

Relationships

 * Tsukuyomi:
 * Geiz Myoukouin/Kamen Rider Geiz: Geiz strongly believes Sougo is Oma Zi-O and is absolutely determined to kill him before he could become Oma Zi-O to prevent the future where Sougo supposedly becomes the tyrant that rules all with an iron fist. He refuses to call Sougo by his real name and cruelly refers to him as Oma Zi-O.
 * Woz:
 * Junichiro Tokiwa :

Past Kamen Riders:

 * Sento Kiryu/Kamen Rider Build:
 * Ryuga Banjo/Kamen Rider Cross-Z:

Portrayal
Sougo Tokiwa is portrayed by So Okuno (奥野 壮). As Kamen Rider Zi-O, his suit actor is Seiji Takaiwa (高岩 成二).

Rider No.
As the leading rider protagonist of Kamen Rider Zi-O, Zi-O is labelled Kamen Rider #35 (仮面ライダー35号) and Heisei Rider #20 (平成ライダー20号).

Etymology
Sougo Tokiwa's name is play on, the place where Shotaro Ishinomori lived and started his manga career during 1956 to 1961. "Tokiwa" also carries the word Toki (とき), which can be translated into time when it is written in kanji "時".

"Zi" in Zi-O's name could mean either time (時) or character (字), representing his "watch" and "Katakana" motifs while the "O" means king (王). It is a pun on English word "Zero".

Appearances

 * Icon-build.png Kamen Rider Build
 * Kamen Rider Build: Be The One
 * Zi-O_logo.png Kamen Rider Zi-O
 * Episode 1: Kingdom 2068
 * Episode 2: Best Match 2017
 * Icon-build.png Kamen Rider Heisei Generations FOREVER