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).

History
Sougo Tokiwa was born on April 28, 2000.

The Birth of Zi-O
When after Sougo was thrown over by his classmate to believe that he could become king someday, he had 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 stairs, a man-like figure, who was revealed to be Woz, a prophet from the future, who tells that this day will be his day to become a king, then later mysteriously vanished.

Later, discovering the fact that his dream was real, Sougo was approached by Woz once again, who then tells him that he'll become an overlord who will reign over the future. While deciding quick of his future Sougo decided to not become a tyrant, but to become a beloved overlord of the future. While in the mist of Kaiji Rider Build's battle with Tsukuyomi, the blank ridewatch, revealed itself to becoming the Zi-O Ridewatch, then Sougo was given the Ziku-Driver by Woz to transform and battle the lusive 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.

Encounter with Sento and Ryuga
Thrown into a hole in time-space after Tsukuyomi's Time Mazine is attacked by Geiz. Sougo 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 appear to help. After revealing their names, Sento and Ryuga brings Sougo to the cafe nascita.

As Ryuga drinks from a carton of milk, Sougo sees the expiration date and realized that he's in the year 2017. Sento affirm that Sougo is indeed from the future since after some analysis, Sougo ridewatch is different in term of structure than Fullbottle. Sougo said to Sento that he comes from 2018, or 1 year in the future. Before Sento asks about the future, Tsukuyomi appears and shot the three of them using Faiz Phone X into unconsciousness. Tsukuyomi apologize as she didn't want Sougo to interfere with the past more than necessary before carried him back to his timeline.

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.

Sougo himself is a layout boy who loves peace and claims that no matter what he will become, the bad things will be over. This is shown when he got thrown into a river in exchange to stop a nearby fight, and him being glad the fight was over, disregarding being thrown into the said river when he was in 1791.

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 - Zi-O Build Form's personal weapon
 * Gashacon Breaker - Zi-O Ex-Aid Form's personal weapon

Vehicles

 * Ride Striker
 * Time Mazine

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).

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