Tsukuyomi (Zi-O)

Tsukuyomi (ツクヨミ) is a woman from the year 2068 who guides Sougo Tokiwa to become Kamen Rider Zi-O.

History
Her past is unknown, as she is a amnesiac and has no recollection of her past. When the Resistance took her in, she took up the codename Tsukuyomi.

In 2068, Oma Zi-O was being attacked by the resistance, which he managed to defeat with minimal effort. After declaring that no one will be able to beat him, Oma Zi-O clenched his fist and killed almost all of the Resistance members, save for Tsukuyomi as she was pushed to a narrow rift by the leader of the Resistance. She then decided to follow Geiz to 2018 to observe Sougo.

The Birth of Zi-O and Another Build
Traveling back to 2018, Tsukuyomi saves Sougo from Geiz and proceeds to show him his future in 50 years, becoming the most evil and despised demonic king in all of history. Despite her attempts however, she is unable to prevent Sougo from attaining the power of Zi-O and is hesitent to trust him, but after watching him, doesn't completely believe he will become Oma Zi-O, something her friend Geiz disagrees with as he proceeds to transform into Kamen Rider Geiz Ghost Armor to destroy Sougo.

Just as Geiz is about to finish off Sougo, she interferes with her Time Mazine and proceeds to take Sogou back to 2018 where they find Another Build is still alive and attacking people. Eventually, she and Geiz are cornered and Sougo saves them, explaining to them that they need to go back to 2017 and destroy Another Build. They travel back and Tsukuyomi watches from the sidelines and Sougo attains the power of the Build Ride Watch and he and Geiz destroy Another Build. Afterwards, she and Geiz decide to live with Sougo at 9-to-5 and monitor Sougo as he gains more power, ready to stop him the day he becomes Oma Zi-O.

Emu Hojo & Another Ex-Aid
Sometime after the Another Build incident, Tsukuyomi and Geiz enroll in Sougo's school to monitor him closely at all times. It's during this observation that a mysterious illness breaks out and the only clue to it is a handheld game that everyone seems to had before becoming unconscious. They eventually conclude that they need to find the Genius Gamer M for help which lead them to Seito University Hospital where they meet Hiiro Kagami and learn that Emu, the one they are looking for, has been missing for a while and the only clue to his whereabouts are a handheld game console and a note written in German. After cracking the code, the team of Sougo, Geiz, and herself are transported to another world where they confront Another Ex-Aid and meet Emu Hojo, Genius Gamer M, and Kamen Rider Ex-Aid. During the confrontation, they learn that Another Riders take the existance of the original Rider away, leaving the latter with no memories of their previous adventures, but still need to deal with the situation. Sougo eventually figures out what Another Ex-Aid, Ida, is after and he and she tries to help Emu by convincing him to stop attacking innocent people to save his son. However, he is too far gone and the only recourse is to destroy Another Ex-Aid's power. Emu gives Sogou the Ex-Aid Ride Watch and watches as Sougo leaves to take care of the situation. Afterwards, everyone returns to 9-to-5 and Tsukuyomi and Geiz are told by Sougo that he trusts them and their judgement and hope to get along.

Amanogawa High School, Another Fourze & Another Faiz
Tsukuyomi and Geiz start looking into another incident involving the dissappearance of school girls that are 18 years old and Libras. Their search brings them to Amanogawa High School, where Gentaro Kisaragi, aka Kamen Rider Fourze, attended school. Despite Geiz's insistance of keeping Sougo out of the situation, Tsukuyomi gets him involved and the three start questioning the students. During that time, Another Fourze makes his appearance as Sogou and Geiz try to defeat him but fail to do so. They are then taken in by the school's Kamen Rider Club and meet its advisor, Chuta Ohsugi, who notices Geiz's Ridewatches and gives Sougo the Fourze Ridewatch saying that Gentaro wanted him to have it. After that, Tsukuyomi does some digging elsewhere, learning about a young girl involved in the last attack on her friends, Karin Yamabuki, and eventually finds her in an abandoned building. She confronts her, trying to get answers when Masato Kusaka and Takumi Inui burst in, causing them to lose sight of her.

Eventually, Tsukuyomi and Geiz learn that Karin has been kept alive by the powers of Another Fourze finding and hunting down 18 year old Libra girls and also learn that Sakuma has been doing this for over 15 years, which explained why he was able to become Another Faiz as well. Eventually, the groups confront Sakuma and Karin and learn of their connection to Masato, being they were from the same private school, and proceed to find and defeat both Sakumas to stop him and her from hurting each other anymore.

Back to 2009 & Learning the Truth
Since Geiz was hesitating to destroy Sougo and prevent the rise of Oma Zi-O, Tsukuyomi started to do a bit more digging into Sougo's past and learned that his desire to become king started after a tragic bus accident. Wanting to learn more, she went back to 2009 and saw Sougo prattling on about becoming a king and saving everyone. She also gets a glimpse of Another Zi-O, Hiryu Kakogawa (but thinks nothing of it). She goes back to the day of the accident and learns a shocking truth about the whole incident: The one who caused the accident and lives of both Sougo and Hiryu's parents was none other than Swartz. She attempted to save Sougo by shooting at Swartz but he blocked the shot, causing it to hit near Hiryu and knocking him unconscious. Swartz then transports all of the kids off the bus and leaves the adults to die in a horrible bus accident that Tsukuyomi would have been caught in as well if not for Tsukasa Kadoya's intervention.

Personality
Tsukuyomi is a no-nonsense individual, but is at least more friendly than Geiz as she tries to convince Sougo several times to not transform into Zi-O for the sake of the future, even willingly saving him from Geiz when the latter attempts to kill him. Tsukuyomi also shown to be quite the observant person as she analyzed Sougo's biography and actions thoroughly to determine whether he's really Oma Zi-O or not.

After Sougo acquired the power of Zi-O II, Tsukuyomi began to have faltering beliefs that Sougo can become a good king. Now since he has powers similar to what terrorized her future, she loses faith in Sougo and sides with White Woz. In spite of her fear of Sougo, she was unwilling to kill the younger Sougo and actually tries to defend him from Swartz. Her doubt would later fade after she learned that Sougo's future to become Oma Zi-O could be altered.

Powers and Equipment

 * Temporal Freezing: Through currently unknown means, Tsukuyomi can temporarily freeze the enemy in time for a few seconds, an ability only Time Jackers have been able to exhibit. However, Her's is more powerful that even can freeze Swartz.

Arsenal

 * Faizphone X
 * Time Mazine
 * Ziku Driver(gag only)
 * Tsukuyomi Ridewatch (gag only)

Relationships

 * Sougo Tokiwa/Kamen Rider Zi-O: Like Geiz, Tsukuyomi believes Sougo to be the evil tyrant Oma Zi-O and decided to go back in time to change his fate. At first, she seemed confused that a light-hearted teenager like Sougo could grow into an evil Demon King. But that quickly changes when she notices his earnest motivation to become a king and his ability to activate the Zi-O Ridewatch. Despite this, she wants to help and guide Sougo in being a hero as Zi-O so time and history can hopefully be altered for the better. But she then loses her faith in him when he becomes Zi-O II. She then reaffirms her mission to kill Sougo, even going as far as time traveling to 2009, seemingly to kill Sougo when he was still a child, while she actually protected the younger Sougo from Swartz after she learned the truth. Once discovering that Swartz was responsible for what had occurred and the possibility of Sougo's future as Oma Zi-O could be altered, her doubt was cast aside as both she and Geiz reconciled with him and return to 9 5 DO.
 * Geiz Myokoin/Kamen Rider Geiz: Geiz and Tsukuyomi were the on the side determined to defeat Oma Zi-O in the year 2068. But after witnessing many casualties, Geiz came to the conclusion that he needs to kill the man who would become Oma Zi-O in the past. Tsukuyomi does not agree with this but Geiz goes back in time. She tries to protect Sougo from him, believing it's not right to kill him for something he hasn't even done yet. After Geiz tries to help Zi-O, she asks him to do what he come for. Although Tsukuyomi remains allies with Geiz, she decides to settle their mission on her own. Upon learning the whole truth, Tsukuyomi later convinces Geiz to postpone his and Sougo’s duel.
 * Black Woz: Tsukuyomi had some knowledge about Woz beforehand, though what she currently knows about him is currently unknown.
 * White Woz: After Sougo became Zi-O II, Tsukuyomi chose to side with White Woz in order to change the future until she learned the truth of Sougo's past and being informed by Tsukasa Kadoya that the future could be changed.

Portrayal
Tsukuyomi is portrayed by Shieri Ohata (大幡 しえり).

Etymology
Her name comes from the moon god  of the Shinto religion and Japanese myth.