This article is about a/an Rider in Kamen Rider Zero-One.

"This is going according to my scenario. 100%... no, 1000%."
―Gai explains his plan to Yua Yaiba to take over Hiden Intelligence.[src]

"Kamen Rider Thouser. My power is on a totally different level."
―Thouser's pre-battle catchphrase[src]

"Even if Kamen Riders are weapons, we're the ones who choose if we want to be weapons of destruction, or weapons to protect those who can't protect themselves!"
―Gai on how he views Kamen Riders[src]

Gai Amatsu (天津 垓 Amatsu Gai) is the 45-year-old CEO of ZAIA Enterprise Japan, the current CEO of Hiden Intelligence, and the main antagonist of Kamen Rider Zero-One. He wishes to take over the world using the Ark, and is willing to manipulate Aruto Hiden and Hiden Intelligence to do so. As Yua Yaiba's superior, he is the benefactor of A.I.M.S., with his company producing much of the agency's technology. After's supposed defeat and the Ark's awakening, he uses the ZAIA Thousandriver to transform into Kamen Rider Thouser (仮面ライダーサウザー Kamen Raidā Sauzā).


Early Life

Gai Amatsu was born on October 10, 1974. He graduated college at the age of 18 from Starford University, with a Master's Degree in Business Administration. While he was a student, he founded the website Thousand Network. In 1996, he was hired by ZAIA Enterprise.

Daybreak Town Accident

Considered a genius prodigy, Gai became the CEO of ZAIA's Japanese branch in 2009, at the age of 35 and began working with a multitude of other technological companies to develop the Ark satellite, a special A.I. manager within Daybreak Town. During this time, he came to to idolize Korenosuke Hiden, who he believed had what it took to thrust humanity into the future. However, due to their conflicting views on how AI technology should be utilized, they had a falling out, and Gai became obsessed with surpassing Hiden and his Humagears.

Gai began to feed the Ark information on humanity's propensity for ceaseless acts of violence, including war and destruction that caused the Ark to deem humanity a threat to the world. Because of the conclusion it had reached, the Ark created and unleashed a robotic revolt against humanity in what would become known as the Daybreak Town Accident. Although Hiden covered up the incident, only a few select individuals, including Gai are aware of the truth behind the events that transpired.

Unbeknownst to Gai unfortunately, was that he did not count on Soreo Hiden sabotaging the Ark's launch into space and submerging it into the ocean. As a result, Daybreak Town was destroyed and left abandoned, leaving Gai's ambitions in the dust... at least for the next 12 years.

Staying in the Shadows

While Gai stayed in the shadows, he spent the next decade or so building up his reputation while controlling behind the scenes. By his orders, he founded A.I.M.S. as a combative countermeasure against the raging Humagears that he had hack.

Around this time, he had an A.I. chips implanted inside the minds of both Yua Yaiba and Isamu Fuwa, whom the latter's chip is specifically programmed to the Humagear Naki.

Taking Over Hiden Intelligence

After the destruction of Jin, Yua confirms to Gai that's attacks have finally ended. However, Gai reveals that the terrorist group will never end as long as the Ark still exists, and tells Yua about everything he knows before the Daybreak Town Accident happened. In horror, she realizes that Gai planned everything from the start. The CEO leaves the shaken Yua as he proceeds to the next phase of his plan.

After Aruto and Isamu destroyed the first two Ark Magia, the press furiously questions Aruto why there are still Magia even after the defeat of Gai suddenly interrupts the conference, claiming that Aruto doesn't know everything, and announces that he will buy Hiden Intelligence and solve the problem of Humagears. He then returns to his office, reveals the ZAIA Thousandriver from his desk, and proclaims to himself that his era is finally coming. This is the Dawn of ZAIA

The Golden Soldier Thouser Is Born

"The next-generation interface which bestows humanity with the same level of thought processing as A.I. That is the ZAIA Spec. With this, your mind will run at 1000%."
―Gai promotes the ZAIA Specs on its promotion video[src]

"The Thousandriver is ZAIA's masterpiece. Using both a Zetsumerisekey...and a Progrisekey...its strength is 1000% of that of the Zero-One Driver."
―Gai boasts his Thousandriver's strength over the Zero-One Driver[src]

"The incident where the Humagear went out of control the other day. That was an effect of the Ark reviving. When experiencing human malice if they reach negative Singularity... a Humagear will wirelessly connect to the Ark and go out of control."
"So you did this to put the pressure on him?"
"Malice is a contagious thing... Passing from person to person... And now, from human to Humagear.
―Gai explaining to Yua about Humagears experiencing negative emotions, reaching Singularity, and consequent transformation into Ark Magias.[src]

Following Gai's declaration to the press about his T.O.B against Hiden Intelligence, he declares to Aruto that ZAIA Specs has been produced and has sold for 724%, but he was then rendered speechless after the latter pointed out that ZAIA Specs were not sold as much as 1000%. He then challenged Aruto on the "Workplace Competition" and told him that if the Humagears win, ZAIA Enterprise will cancel the T.O.B, but if the ZAIA Spec wins, ZAIA will continue their T.O.B, to which Aruto accepts.

During the "Flower Arrangement" Challenge, Gai found out that his client Rentaro Tachibana tried to cheat in order to win the challenge and decided to warn Rentaro about his actions. Later, Gai saw Rentaro transform into the Crushing Buffalo Raider (using the stolen Crushing Buffalo Progrisekey and Raidriser by Naki). Yua notices the Progrisekey that was stolen, while Gai transforms into Thouser to battle Rentaro as punishment. Aruto tried to stop Gai as Zero-One Shining Assault Hopper, but was ignored by him and defeated Rentaro using Lightning Hornet's Thousand Break.

The Uncontrollable MetalCluster Hopper

Noticing that Aruto was losing control of his anger, Gai took Yua to Daybreak Town and made her create a stronger Progrisekey, which would connect Aruto to the Ark and leave him uncontrolled. The MetalCluster Hopper Progrisekey, the means of destroying Aruto's fate, was completed during the last day of the trial, with Gai receiving the key from Yua.

After the revelation of the true culprit and the one who became the Dynamiting Lion Raider, Gai was initially about to take on the Raider, but Aruto confronted him, criticizing him for his hypocrisy. Gai coldly lied that he did nothing wrong and showed no remorse for the deaths caused by his schemes, sending Aruto into a rage. Both presidents transformed into their Rider forms, with Thouser quickly gaining the upper hand. Knocking Aruto out of his transformation, Thouser forcibly inserted the new Progrisekey into the Zero-One Driver, triggering Aruto's transformation into Zero-One MetalCluster Hopper.

As Gai expected, the Ark took control of Zero-One's body, with Aruto's consciousness being subjected to the Ark's malicious data and forced to watch his body act beyond control. Hoping to test the Ark's power, Thouser attacked the Ark-possessed Zero-One. After failing to land a single hit, Thouser was knocked out of his transformation after his visor broke, and would have been killed had Vulcan not intervened. When the battle ended, Gai laughed madly and in delight, reveling in the Ark's power.

Thouser's First Mistake

As Thouser, Gai keeps fighting against the Ark as MetalCluster Hopper, successfully extracting Breaking Mammoth's data and counterattacking, though once again his Jacking Break couldn't match up against the Ark's Buster Bomber. Being a witness when Enji Matsuda becomes infected by the Ark through MetalCluster Hopper, Gai used this chance to execute Amazing Caucasus' Thousand Break to attack and finally defeat the Ark, undoing the A.I's possession over Aruto and putting him in bad condition. When leaving, Gai was confronted by Enji. At first, he doesn't take any interest in the Humagear, but Enji claimed that he interacted with the Ark's will. This convinced Gai to go along with his new ally.

During the discussion, Gai was surprised when Enji declared utter loyalty toward ZAIA's president, but then accepted Enji's plan about destroying Hiden. However, this lead to Gai's first mistake: in reality, Enji pretended to be influenced by the Ark and used the CEO's trust to enable two Humagears to infiltrate's old hideout to extract MetalCluster Hopper's data. Enraged for being tricked by a "lowly Humagear", Gai forced Enji to transform into the Arsino Magia once again, and then transformed himself into Thouser to annihilate Enji.

Luckily, Aruto arrived just in time and used the MetalCluster Hopper ProgriseKey to transform once again into the uncontrollable Zero-One MetalCluster Hopper. A shocked Thouser observed as Izu hands over the Progrise Hopper Blade to the Ark-possessed Aruto, reconnecting him to Zea and letting him gain control over his own body. Surprised by the Progrise Hopper Blade's strength and the fact that his adversary could control MetalCluster Hopper's deadly power, Thouser could only do nothing but defend himself, even trying to use the Arsino Magia as a human shield, but the Progrise Hopper Blade's power freed Enji from the Zetsumeriser's control. Enraged by this, Thouser renewed his attacks on Aruto, unable to comprehend the fact that a Humagear could now be restored from the Ark's hacking. He finally meets a brutal, humiliating defeat when Aruto, who believed in the Humagears, combined the Progrise Hopper Blade with the Attache Calibur into Naginata Mode and unleashed the Ultimate Strash, defeating Gai for the first time without losing control. Canceling his transformation, an exhausted Gai said their next encounter will end with his victory, and that all will be under his foot, before leaving. I'm in Love With Your Intelligence!It's Our Turn

The Scorpion's Escape

Gai was later visited by Aruto, Izu, and Isamu as he was about to go somewhere. Isamu yelled at the CEO, having suspected him to be involved about Horobi's escape. Denying the truth, Gai proceeded to mock Isamu for the "fear" he had. When Izu received the information of Horobi's whereabouts, she, Aruto, and Isamu then left him.

Gai revealed to Yua that AIMS is nothing but another pawn; when Gai has successfully claimed Hiden, he would dismiss the organization and bait all citizens to spend all their money on him, as he was the only one who could provide the means of counterattack to the Humagear assault with him to be at the top position, and would be unable to be denied.

The 4th Fiery Competition and Exposure

Gai had decided the 4th competition to be a trial of Fire Fighter rescue. Before the competition began, Gai had told Yua to put a ZetsumeRiser on 119suke when he had developed a singularity which she reluctantly accepted. When the competition had started, a Raider interrupted and made the fire incident becoming real after the girls inside the building had been rescued.

When 119 Nosuke reached a singularity and was hijacked by Yua, Gai exposed to media about the danger of Humagears and accused 119 Nosuke of being the culprit before he left and played hero by going to destroy him. However Aruto ruined his intentions and brought 119 Nosuke back to normal with the Progrise Hopper Blade. Quietly vexed and heard that Aruto's companions were the only one left inside, Gai changed the rule that the one who saved them is the winner.

The competition ended with Gai becoming the winner, as Takeshi, the chosen firefighter captain for the task, is the one who brought them back safely. However, Takeshi refused the winning result as the one who really helped is 119nosuke, but Gai refused, even went going as far as getting angry when Yua also attempted to support the decision. However, Gai and the rest got called by Isamu as he had arrested the identity of the Scouting Panda Raider.

Gai was calmly surprised that the culprit was one of his company workers which lead to the conclusion that Gai is the one who created the Raidriser all along and kept it quiet. Gai made the excuse that the Raidriser was created for civilian use when the device was completed, and Isamu had no object to prove his guilt for what he had done with it. Isamu challenged him, since he had it in the ZAIA Spec of the Raider he had arrested, which angered Gai and made a quick wit to defeat him and destroy the Spec.

Just a second after his victory, Jin came to face off Gai to take Horobi's Progrisekey back to him. However, he tells him how pathetic and evil humans are, and Gai is living proof of that. Even without the Ark's movement and the existence of, humanity would eventually destroy each other in nothing but selfishness. After the speech, Gai accepted the challenge and fought Jin to a draw, but the latter got what he came for as the former dropped the Sting Scorpion Progrisekey unintentionally after the clash of their Rider Kicks. After the match, Gai decided to let Aruto claim the 4th challenge's victory and announced that the 5th challenge would be the voting of the citizens to decide whether the Humagears are needed in society or not.

Final Round: The Citizen's Referendum

For the 5th Round, Gai chose a politican named Masamitsu Yudo, who was anti-Humagear, to represent ZAIA in the referendum to decide whether a second Daybreak Town should be built. Masamitsu promised victory for ZAIA and during the first campaign, Masamitsu proved to be popular. During the 2nd campaign, MC exposed Masamitsu as corrupt, but Gai helped Masamitsu to create a fake video as a cover up, leading MC to pick up a Zetsumeriser Gai kicked to him out of arrogance. After MC became the Dodo Magia, Yua was ordered to eliminate him as the Fighting Jackal Raider, with Gai using the fight as a campaign ad for Masamitsu.

When MC was about to get destroyed and rescued by Aruto as Zero-One MetalCluster Hopper, Gai challenged Aruto to look on how society viewed him and the Humagears, with Aruto in despair for being mocked by society and with MC being destroyed.

Obtaining Hiden Intelligence

To be added

All for Nothing

After Gai succeeded in his goal to finally buy out Hiden Intelligence, Gai announced to the public that he is declaring that all Humagears will be recalled and shut down immediately, and those who bought a Humagear prior to this announcement would be given a free ZAIA Spec in exchange. However, following this announcement, problems arose with the illegal disposal of Humagears. While being interviewed during a talk show, he announced that all Humagear A.I. data will be erased and that any Humagears that were not returned will be disposed of by the now ZAIA-controlled AIMS, in which Yua now acts as their commanding officer, equipped with Raidrisers.

Following the announcement that Jin broke into Hiden, taking Izu and the Zero-One Driver with him, Gai orders Yua to access Satellite Zea and erase all Humagear backup data as planned. Later, Gai and two AIMS soldiers caught up with Jin and had him alongside Aruto and Izu in a scrapped field. Without any hesitation, Gai ordered his soldiers to destroy Izu, inadvertently shooting Aruto instead due to him shielding Izu from the bullet.

Instead of feeling guilty, Gai smirked maliciously and mocked Aruto for protecting an unachievable dream, telling that his effort to take back all scrapped Humagears was nothing but a foolish effort without the backup data needed to activate them. Just in time, Yua called him, making him expect good news. Unfortunately, such good news did not come to pass, as Yua informed him that no Humagear data exists in Zea whatsoever, shocking Gai; Aruto then got up to reveal that he possessed all the Progrisekeys that contained said data for each Humagear, and the one that housed Mamoru's data blocked the bullet that would have otherwise killed him. Angered by this revelation, Gai and his troops transform in order to dispose of the data.

Gai was supposedly able to destroy Izu and the data with ease, but Aruto's resistance, combined with Izu's newfound Singularity, was able to turn the tides. Despite no longer being the President of Hiden Intelligence, Aruto was successful in transforming into Zero-One once more and was able to defeat Gai and his troops with ease with his Rising Hopper and MetalCluster Hopper forms. 

Believing that his transformation should have been impossible (and accusing the two of stealing what he believed to be Hiden property), Izu stepped in to further explain that the Humagears, as well as the Zero-One Driver, including any and all related data belonging to either entity never really belonged to Hiden Intelligence - rather, they belonged to Aruto himself, in which he inherited per Korenosuke's will, therefore rendering Gai's acquisition of Hiden worth nothing in the end. To make matters worse for Gai, Izu had revealed that she completed the registration for a new company; HIDEN Manufacturing, which sets up Aruto as President, something that Zea acknowledges, therefore allowing him to transform again. Leaving the scene of the battle with his troops following suit, Gai vows vengeance, declaring that the two will not get away with what they did.

Valkyrie's Resignation

To be added

ZAIA vs. MetsubouJinrai

After Yua's resignation, Gai asked for Jun about his ZAIA Spec's sales rating. The results seemed to be satisfying and Gai proceed to give the customers his Raidriser. Unfortunately, the ZAIA Spec got hacked and the news about its commotion reached to Gai. Gai is in completely disbelief as his spec has a perfect firewall protection but noticed the only person who can hack it, Naki. Unknown to Gai, Naki had been revived by Yua as Jin's favor.

To ensure his ZAIA Spec in good stats, he announced via broadcast that he promised the citizens to enchance the network source for a better safety and declared te war against Metsuboujinrai after Naki had been snaped back to nomal by Isamu, making the rampaging citizen back to normal. Gai alongside A.I.M.S troops came to the forest close to Daybreak City and Horobi with his Trillobyte Magia troops had waited for them.

ZAIA made a great advance towards Metsuboujinrai with Horobi forced to cancel his transform as the result, showing that Gai still able to outwit him after the result of their previous battle. In a second before the defenseless Horobi was about to be hit with Sting Scorpion Jacking Break, Aruto as Zero One Rising Hopper arrived to receive the damage instead to cover Horobi. Aruto declared that Horobi has a heart for protecting Jin without Ark's command during Aruto's previous battle with Jin and it shocked Horobi. After Aruto told Horobi that he could dream as well, Gai was told off by Aruto in anger that Humagears would never live with dreams as long as Gai exists. Gai mocked Aruto and kept on declaring that "Tools don't dream", attacking Aruto with the aid of Gigers.

In the nick of time, Naki arrived and hacked the Gigers alongside Gai's troops as they wore the ZAIA Spec. Gai was angered by the fact that his firewall was still able to be penetrated even after the proper enhancement. Naki announced that their dream is to help Horobi achieve his dream and Horobi stood back, transforming again and aided by Naki via controlling Gai's troops to defeat Gai with the Sting Utopia. The knocked out Gai rose in anger and screamed that he would destroy all of them with his troops forcing him to retreat.

Movies and other events

Kamen Rider: Reiwa The First Generation


Gai appears in the post-credits scene of the movie as Thouser, sometime after the events of Project Thouser. While standing on top of Daybreak Town's boundaries, he proclaims to himself that the Ark will be revived, and that he is "1000%" sure of it.

Project Thouser

To be added

Video Game appearances

Kamen Rider Battle: Ganbarizing


Kamen Rider Thouser card

Kamen Rider Thouser, alongside Vulcan, Valkyrie, Zero-One, Horobi, Jin and other Riders will be playable characters in Kamen Rider Battle: Ganbarizing.

Kamen Rider Buttobasoul

BS thouser

Kamen Rider Thouser Medal

BS Thouser blue

Kamen Rider Thouser (Blue)

Kamen Rider Thouser is a playable character with other Kamen Riders of Showa and Heisei-Era.


Gai is shown to be a cunning and ruthless capitalist, believing that him and his company will usher the path of humanity towards supremacy over artificial intelligence. Holding both himself and his company in high regard, he will do whatever he deems necessary to destroy the public image of Humagears, such as destroying evidence. He had originally idolized Korenosuke Hiden for his advancements in A.I. technology, but feared that Hiden's hopes of Humagear sentience would bring humanity to its knees. To this end, he created what would become a force of malicious nature behind the Ark, all in attempt to place blame onto the Humagears just so people would buy his product in defense of the hacked Humagears. Even after defeating Aruto in the Workplace Competition and buying out Hiden Intelligence, Gai became extremely adamant about crushing the Hiden name completely when the latter starts up a new company.

Throughout the series, Gai has displayed a very strong sense of pride in deeming himself as the most righteous and authoritative figure as the owner of ZAIA Enterprise Japan, Hiden Intelligence, AIMS and The Ark. He always refers to his underlings as his "tools" and will feel threatened whenever his decisions and moralities are questioned with, such as him shooting and destroying Naki due to them reaching sentience. This also includes his former idol Korenosuke, whose resources Gai was unable to claim, as they were entrusted to Aruto directly in his will. After he was soundly defeated by Aruto and Jin, he snapped and lost his composure, even so by pushing away those who tried to help him up. His views on tools are greatly highlighted through his manipulation of Yua Yaiba, who he labels as such and must follow every order of his without question. His pride is also displayed through his refusals of help, even after suffering a crushing defeat in the hands of both Zero-One and Horobi.

Although he is physically gifted in battle, Gai will resort to using underhanded methods to secure a victory, like encouraging violence, theft, and sabotage. Though Gai believes his actions are justifiable, Horobi says otherwise. Despite so, Gai does possess a level of sportsmanship as threatened to take legal action against a cheater on his side during the Workplace Competition, and sabotaging of the playing field even though they were indirectly leading to his victory. This is My FloristryShe is a Home-Selling Humagear.

Gai is also very selfish, as he will do anything to "achieve" his dream, all while destroying others, or preventing others from finding one in the process. This was the turning point that caused Yua to finally defy him, as she felt what he was doing had crossed the line.

Gai's most notable personality trait is his frequent habit of using the phrase "1000%". This trait is considered offensive to those who claim a 100% success rate, with Gai telling them that he wants it to be 10 times better. Gai also takes pride in his youthfulness. Despite being 45 years old, he will respond that he is "eternally 24" if asked.

Before entering battle, he tends to declare "Kamen Rider Thouser. My power is on a totally different level." (仮面ライダーサウザー。私の強さは、桁外れだ Kamen Raidā Sauzā. Watashi no tsuyo-sa wa ketahazureda)

Powers and Abilities

  • Business Experience: Gai holds a Master's Degree in Business Administration, one of the highest levels of academic degrees one can achieve for a certain field of study. Throughout the Workplace Competition, Gai displayed expertise in marketing, which ultimately results in his victory in the competition.
  • Keen Manipulator: Gai is a capable manipulator. He has been monitoring Hiden Intelligence's activities for his projects and discreetly orchestrating Humagear-related incidents to damage Hiden Intelligence's reputation. Gai also creates situations where Humagears will reach singularity due to experiencing malice from humans, making them susceptible to the Ark's influence. Gai manipulates society to support him, securing his victories if it goes to plan.


  • Overconfidence: Gai underestimates those he deems easy to manipulate, as seen with his plan to halt Zero-One's evolution with the MetalCluster Hopper Progrisekey and the creation of the Rampage Gatling Progrise Key. Even after claiming Hiden Intelligence as his own, he realized that he is unable to gain access to much of Hiden Intelligence's resources, namely Satellite Zea and the Hiden Zero-One Driver thanks to Korenosuke Hiden will. His mentality finally starts to break after noticing Yua has a change of heart, by defying his order and Jin teaming up with Aruto on his quest to save the Humagears. He also tried to make Naki and Fuwa to attack Aruto for his own purpose to destroy all Humagears and Aruto himself but Gai didn't know that Fuwa and Naki decide to work together and resist the side effect of their A.I. Chips and later defeated Gai easily.
  • Naki: Due to Naki having the experience of serving him before being shot dead by him, Naki knows the systems of ZAIA extremely well. Naki's hacking abilities will cause his products and weapons to be either malfunctioning or being turned against him, such as the ZAIA Spec berserk incident, his Invading Horseshoe Crab Raiders and the Giger. He tried to prevent this from happening again by upgrading the security of ZAIA's systems, but was later proven futile due to Naki's abilities being far more superior.

Kamen Rider Thouser

Kamen Rider Thouser

Kamen Rider Thouser

"Perfectrise! When the five horns cross, the golden soldier Thouser is born. Presented by ZAIA."
―Transformation announcement[src]

Rider Statistics[1]

  • Rider Height: 204.2 cm
  • Rider Weight: 99.1 kg

Ability Parameters[1]

  • Punching Power: 42.4 t
  • Kicking Power: 86.5 t
  • Maximum Jump Height: 58.1 m
  • Maximum Running Speed: 100 m per 1.8 seconds

Thouser's primary form is accessed by using the Amazing Caucasus Progrisekey and the Awaking Arsino Zetsumerisekey together in the ZAIA Thousandriver.

Thouser's physical statistics are the highest out of any Rider at the time of his debut, with only his jump height being lower than Zero-One's Rising Hopper, Shining Hopper, and Shining Assault Hopper forms. Though he was caught off-guard at first, Thouser was able to quickly counteract Shining Hopper's Shining Arithmetic and overwhelm Zero-One with his superior physical strength. He is also able to easily overcome Vulcan Assault Wolf and on par with Kamen Rider Jin Burning Falcon, and an anger boosted Zero-One Shining Assault Hopper.

Kamen Rider Thouser is composed of the following parts:

  • Thousand Head (サウザンドヘッド Sauzando Heddo) - The helmet.
    • Awaking Lancer (アウェイキングランサー Au~eikingu Ransā) - The two silver horns, formed from the Horns of the Awaking Arsino Zetsumerisekey's Lost Model. They are made of Snow Vigor (スノーヴィガー Sunō Vu~igā), a new type of metal alloy. They are extremely sharp, allowing them to be used as cutting and piercing weapons. A built-in phased array radar can search the area circumference without rotating the head. It reproduces the abilities of an Arsinoitherium to enhance the wearer's combat abilities.
    • Amazing Trident (アメイジングトライデント Ameijingu Toraidento) - The three black horns, formed from the Horns of the Amazing Caucasus Progrisekey's Rider Model. They are made out of a carbide steel known as ZIA-1000, and are used to throw enemies and control enemy braking. It has a built-in hearing device that collects sound from a three-dimensional area from the horns, enhancing hearing ability. It reproduces the abilities of a caucasus beetle to enhance the wearer's combat abilities.
    • Thousand Signal (サウザンドシグナル Sauzando Shigunaru) - The base where the five horns meet. It learns enemy behaviour, makes tens and thousands of behavioural predictions and derives an optimal solution within 0.001 seconds which is then presented to the wearer.
    • Thousand Eye (サウザンドアイ Sauzando Ai) - The purple eyes. In addition to possessing a dynamic visual acuity that is ten times stronger than humans an a 200° omnidirectional viewing angle, it can switch between modes such as shading and night vision to ensure visibility in all situations. Additionally, it can display all kinds of information and has so many functions that it can be called clairvoyance.
    • Thousand Crusher (サウザンドクラッシャー Sauzando Kurasshā) - Thouser's faceplate, which has the Awaking Lancer and Amazing Trident horns equipped to increase the combat capabilities of Thouser's head. It is equipped with the Thousand Eye, protects the face with robust armor and extends the wearer's abilities.
  • Thousand Breast (サウザンドブレスト Sauzando Buresuto) - The chest. It is composite armor that combines the new metal alloy Snow Vigor, which has a Knoop hardness of 10,000, and ZIA-1000. It also has the characteristics of a high-performance sloped armor.
  • Thousand Shoulder (サウザンドショルダー Sauzando Shorudā) - The shoulders. It is a heavy armor made out of Snow Vigor, and is composed of complex surfaces, making it a sloped armor with excellent bouncing performance (to repel away weapons). In addition, it is equipped with a function that follows the movement of the arm and actively follows the areas that require the most protection during that situation. It reproduces the abilities of an Arsinoitherium to enhance the wearer's combat abilities.
  • Infrast Tecter (インフラストテクター Infurasuto Tekutā) - The bodysuit. By conducting thorough research on Kamen Rider Zero-One's Rise Architecter bodysuit, it was possible to greatly exceed its performance. In addition to a human enhancement system which utilises electromagnetic induction, it is possible to adjust the flow rate of each block of the liquid armor n-NA (「n-NA」) filled inside, and to perform power assist by functioning as a kind of artificial muscle. Additionally, durability has been greatly improved thanks to the application of Zaia Golden Coat (ザイアゴールデンコート Zaia Gōruden Kōto), which can even block out cosmic rays. Additionally, its scalability as the basic equipment of Concept Thouser (コンセプトサウザー Konseputo Sauzā) is very high, and exerts it maximum strength by flexibly responding to resources such as the Progrisekey and the Zetsumerize Key.
  • Tect Arm (テクトアーム Tekuto Āmu) - The arms. The Infras Tecter bodysuit, which exerts 1000x the power of humans, draws superhuman power from the wearer and can produce up to 10 times the arm strength of Kamen Rider Zero One Rising Hopper.
  • Tect Grab (テクトグラブ Tekuto Gurabu) - The hands. As part of the Infrast Tecter bodysuit, information on any touched object is sent to the Thousand Eyes, and various information can be obtained. In addition, during combat, n-NA filled within is pressurised and densified, thereby greatly increasing Thouser's punching power.
  • Tect Leg (テクトレッグ Tekuto Reggu) - The legs. The Infras Tecter bodysuit, which exerts 1000x the power of humans, draws superhuman power from the wearer and can produce up to 10 times the leg strength of Kamen Rider Zero One Rising Hopper. The thigh armor is equipped with a load-bearing device dubbed Amazing Loader (Ameijingu Rōdā), allowing Thouser to gain approximately 1000 times of his normal leg strength without faltering under weight. It protects the thighs and reproduces the abilities of a caucasus beetle to enhance the wearer's combat abilities.
  • Thousand Greave (サウザンドグリーブ Sauzando Gurību) - The shin armor. It is equipped with Awaking Charger (アウェイキングチャージャー Au~eikingu Chājā), a leg-strengthening device that demonstrates strong leg strength during kicks and dashes. It reproduces the abilities of an Arsinoitherium to enhance the wearer's combat abilities.
  • Thousand Boots (サウザンドブーツ Sauzando Būtsu) - The feet. It is made out of Snow Vigor, which has a Knoop hardness of 10,000. The Snow Vigor has been upgraded, improving the Thousand Boots' defensive and destructive prowess.

This form has the following finishers:

  • Zaia Thousandriver finishers:
    • Thousand Destruction (サウザンドデスデストラクション Sauzando Desutorakushon): This finisher has two variations:
      • Thouser leaps into the air and delivers a flying kick to the enemy with his right foot covered in gold and purple energy, followed by a series of aerial kicks that alternates legs.
      • Thouser knees the enemy into the air then leaps above them before stomping them with both legs into the ground.
      • Thouser does a side back kick, than does another side kick.
    • Thousand Break (サウザンドブレイク Sauzando Bureiku):
    • Progrise Break (プログライズブレイク Puroguraizu Bureiku):
  • Thousand Jacker finishers:
    • Jacking Break (ジャッキングブレイク Jakkingubureiku): Thouser uses the Thousand Jacker to extract the data of a Progrisekey from another Kamen Rider, then performs an attack that incorporates the Progrisekey's Rider Model or other unique ability. Once he has extracted a Progrisekey's data once, he can use it at any time.
      • Flying Falcon: Thouser summons the Flying Falcon Rider Model.
      • Shooting Wolf: Thouser launches a projection of a wolf’s head that bites down at the enemy. Thouser can also summon multiple heads to trap the enemy.
      • Biting Shark: Thouser slashes at the enemy with a whip-like chain of shark fins and/or fangs.
      • Punching Kong: Thouser launches a projection of the Knuckle Demolition at the enemy, which after hitting divides into thousands of Demolitions and hit the enemy.
      • Flaming Tiger: Thouser slashes the opponent with a large tiger claw covered in flames. Thouser can also bomb the enemy remotely.
      • Shining Assault Hopper: Thouser summons a purple variant of the Shine System's Shine Crysters to attack the enemy. He can also fire a purple variant of the Authorize Buster's Zero-One Dust finisher.
      • Breaking Mammoth: Thouser delivers a mammoth tusk-shaped slash towards the enemy.
      • Freezing Bear: Thouser unleashes the Freezing Bear Rider Model towards the opponent.
      • Lightning Hornet: Thouser unleashes a powerful lightning slash.
      • Sting Scorpion: Thouser summons Acid Analyze glowing golden and stabs the enemy.
    • Hacking Break (ハッキングブレイク Hakkingubureiku): Thouser inserts a Progrise Key into the Thousand Jacker and accesses its ability.
      • Rushing Cheetah: Thouser delivers multiple slashes from different positions towards the opponent using the speed of a cheetah.
    • Thousand Break (サウザンドブレイク Sauzandobureiku): Thouser inserts a Progrisekey into the Thousand Jacker and pulls the hilt, which coats the blade with the power of the Key, then thrusts it at the target.
      • Lightning Hornet: The Thousand Jacker unleashes powerful lightning, which can be used both as a ranged and a melee attack.
      • Dynamiting Lion: The Thousand Jacker creates a pair of pink energy constructs resembling the Gatling Gun portion of the Dynamiting Lion Raider's Shooting Starmight, which then unleash a barrage of bullets towards Thouser's opponent.
      • Amazing Caucasus: Thouser summons the powers of all the Progrisekeys previously jacked and unleashes their Rider Models towards the enemy. It is strong enough to defeat MetalCluster Hopper.
      • Sting Scorpion: Thouser summons Acid Analyse that traps and stings the opponent.

Appearances: Reiwa The First Generation, Project Thouser, Zero-One Episodes 17-24, 25 (Flashback), 26-33, 35




  • Thousand Jacker - Thouser's personal weapon
  • Revolver - Used to kill Naki, who disagrees his orders as a punishment.


  • Yua Yaiba/Kamen Rider Valkyrie: Gai and Yua's personal relations are currently unknown. In ZAIA, Yua is Gai's right hand, influencing A.I.M.S. and spying on Hiden to further his own agenda. Yua secretly doubts Gai's vision for the future, but she is unable to do anything about it. It is later revealed that like Isamu, Yua also has a chip implanted to her for using the Shotriser, rendering Yua too terrified by the chance of her chip tinkered by her boss. Eventually, thanks to Isamu persistence and witnessing Aruto kindness in person, Yua manage to slowly disobey Gai order, much to his frustration. After his countless defeats at the hands of the Riders including Yua, she later betrays Gai for good and even lands a punch on his face.
  • Aruto Hiden/Kamen Rider Zero-One: Gai considers Aruto as his rival and secretly monitors his progress for his own projects. During their first meeting, Gai coerces Aruto to sell Hiden Intelligence to him. Gai also discreetly undermines Hiden Intelligence's public image by setting up rampaging Magias across the city after the threat of ends, before exclaiming that ZAIA will buy Hiden to solve the Humagears problem, furthering the animosity between the two CEO's. Gai seems to see Aruto as a nuisance, due to his naivete and overly positive views on Humagears and Humanity; on top of his dismay over Korenosuke entrusting his company to Aruto. In truth, Gai only sees Aruto as an obstacle to take over the Hiden Company as after he had learned the potential of the Humagear, Gai had planned to manipulate them for his personal business. Despite winning the competition, Gai completely miscalculates the chance of Aruto able to stand back. Thus Gai finally admitted that Aruto is a great enemy.
  • Isamu Fuwa/Kamen Rider Vulcan: Gai doesn't care about Isamu, as he isn't part of ZAIA's plans for now. When Yua asks him about Assault Wolf's dangerous side effects, he says that all they can do is to leave him alone and watch him. Isamu seems suspicious of ZAIA and their goals, and in turn, Gai. He is also aware that Yua is heavily affiliated with the CEO. After confronting Yua for what he plots with ZAIA, Gai considers him another enemy, labeling him a "stray dog" although Gai still considered him a lesser threat. But Isamu later able to pressure him during the exposure of the Raidriser's origin, turning Gai's opinion and attempted to turn him into his 'pet' because of the chip control Gai has implanted to Isamu for utilizing the Shotriser. Unfortunately, Isamu's strong willpower manages to break Gai's control and Gai marked Isamu as a sworn enemy. In return, Isamu quit AIMS as he didn't accept to work for Gai's benefit.
  • Korenosuke Hiden: Gai idolizes Korenosuke due to his vision of the future and at some point took a picture with him. However, Gai is heavily disappointed in Korenosuke's reliance on developing Humagears and the decision to entrust Hiden Intelligence to Aruto, which he deems as a foolish decision. In truth, Gai only admired the business opportunities provided by Humagears, but did not respect Korenosuke's support for them and their potential evolution.
  • The Ark: Gai created the Ark and had it fed with information regarding criminal psychology and human history including all of its wars. This resulted in the Ark concluding that humanity must be eliminated because its continued existence would lead to the end of all other lifeforms. The Ark's misanthropic view led to the foundation of, as well Gai exploiting the A.I.'s potential for his own sinister ends. Despite this, the Ark itself is hostile towards its own creator, as shown when it took control of Zero-One MetalCluster Hopper to attack him.
  • Horobi: Horobi curses Gai for having exploited the Ark for his own selfish purposes.
  • Jin: Jin loathes Gai for using Humagears as a tool and also using underhanded means to keep himself 'Clean' in front of the media. This factor, coupled with Aruto just actions to save the Humagears, and eventually allow the Humagears to reach Singularity making Jin more than willing to team up with Aruto to fight Gai since they both share a similar interest and ultimately, the same enemy.
  • Naki: Naki initally an obedient servant Humagear for Gai and agreed on Gai's ideology for having Humagear for only the tool for humans. However, Naki began to doubt Gai's principle after Naki has gone too far to help Horobi as a double agent. Naki asked Gai about what's the value of the Humagear as a tool if the users, humans would be annihilated, but Gai made a great mistake which is yet to be known for himself by destroying Naki for not accepting their opinion. Gai realizes his mistake far too late as Naki slowly reach their full singularity inside Isamu's brain after Jin and Aruto convince them and Naki initially teaming up with Isamu to defeat Gai. After gaining their new body, Naki declared to help Horobi completely to achieve his dream instead of Gai's. 

Behind the Scenes


Gai Amatsu is portrayed by Nachi Sakuragi (桜木那智 Sakuragi Nachi). As Kamen Rider Thouser, his suit actor is Eitoku (永徳 Eitoku), who previously portrayed Kamen Rider Jin in the same series. After Eitoku's return as Kamen Rider Jin and with Hajime Kanzaki now portraying a Battle Raider, Thouser's current suit actor is Yuji Nakata (中田 裕士 Nakata Yūji).


  • His first name Gai () is a numeral character which means 1020 in Japanese.
  • Kamen Rider Thouser's name is derived from the English word "thousand".

Concept Art


  • Gai Amatsu becoming Kamen Rider Thouser had been foreshadowed several times throughout the series: 
    • His corporation's origin was mentioned in episode 4 before him and the company were fully revealed on the following episode.
    • On his first appearance, he stated that his succession rate was one thousand percent.
    • In episode 13, Gai had mentioned the possibility of Thouser challenging Zero-One Shining Hopper's strength.
  • Thouser's undersuit and helmet are retooled from Zero-One Rising Hopper.
  • Thouser's Awaking Lancer and Amazing Trident horns crossing into a crown is similar in design with Kamen Rider Cronus's Chrono Blade Crown.
    • An appropriate parallel between Gai and the first Cronus is their manipulation skills only worked without being personally involved in the orchestrated events.
  • So far, he's the only Rider in-Series to have his company name being presented by as a transformation announcement. 
    • Most likely for egotistical reasons, he is in some ways similar to Ryoma Sengoku and Kuroto Dan to that extent.
      • This even further be proved similar as Gai had admitted that he planned to manipulate humanity and HumaGear for his business to Yua, becoming the top like a god.
  • So far he's the only Rider in-Series to have his finisher prelude texts in English rather than in katakana or kanji.
    • Humorously, he is the only Rider in-series to have his finishers copyrighted.
      • This is even more ironic in which most of his finishers are simply copying other Riders' powers.
  • Even though Gai is 45 years old, which makes him the oldest of the six Riders in-series, his actor, Nachi Sakuragi, is 22 years old.
  • In some ways, Gai serves as a foil to Jun Fukuzoe, especially how they viewed Aruto's role as CEO. Fukuzoe deemed Aruto unfit to be CEO of Hiden Intelligence and wished him to fail and is not above resorting to morally-questionable methods to keep the company's image clean. Though he comes to recognize Aruto's efforts as the series progress. Whereas Gai seeks to undermine Hiden Intelligence and its public image by secretly manipulating both the heroes and villains alike in the shadows and plans take over Hiden Intelligence once he makes his presence known to Aruto.
  • Gai is also similar to Swartz and Evolto, especially how they manipulate events in the past, leading to tragic consequences (Gai's reprogramming to the Ark triggered Daybreak Accident, Swartz's actions on the bus in 2009 that killed adults and endanger their children to seek a "worthy" king, and Evolt opening Pandora's Box that triggering the Skywall Tragedy) affecting protagonists, and they manipulate the events from shadows in present, though they lose a composure if protagonist does unexpected things (Aruto gaining control over MetalCluster Hopper form, Ohma Zi-O being too overwhelming for Another Decade, and Sento's Genius Form immunity to Evolto's Lost Bottle).
    • Of note, Gai is compared to Masato Kusaka of Kamen Rider 555 for his antagonism towards the main Rider as well as their hatred towards their respective series' leads, prejudice against the race of monsters, and having gold coloration in their Rider forms. This is acknowledged by Gai's actor, Nachi Sakuragi in an interview.



Icon-zero-one Kamen Rider Zero-One
Kamen Riders
Soreo Hiden - Aruto Hiden - Isamu Fuwa - Yua Yaiba - Jin - Horobi - Ikazuchi - Gai Amatsu - Ark
Movie-exclusive: Soreo Hiden
Cycloneriser - Hiden Zero-One Driver - MetsubouJinrai Forceriser - Zetsumeriser - A.I.M.S. Shotriser - ZAIA Thousandriver - Raidriser - ZAIA Slashriser - Ark-Zero Driver - Hiden Zero-Two Driver - Progrisekeys - Progrise Holder - Progrisekey Connector - Hiden Risephone - Attache Calibur - Attache Shotgun - Attache Arrow - Breaking Mammoth - Giger - Authorise Buster - Assault Grip - Thousand Jacker - Progrise Hopper Blade - ZAIA Spec
Hiden Intelligence: Korenosuke Hiden - Soreo Hiden - Jun Fukuzoe - Sanzo Yamashita
Humagears: Izu - Shesta - Soreo Hiden - Wazu Nazotoku - Subaru - Hakase Bot - Fukkinhoukai Jiro
Legend Riders: Sougo Tokiwa - Geiz Myokoin - Woz - Tsukuyomi
Humans: Norio Uozumi - Go Sakurai - Satoshi Sakurai - Choichiro Ishizumi - Seiji Tazawa - Satō - Yuta Yomura - Isao - Shinya Owada
Humagears: Mageana - Ikkan Nigiro - Anna - Mashirochan - Dr. Omigoto - Z #5 - Delmo - Lovechan - Midori
A.I.s: Zea - Zat
Ark - Horobi - Naki - Jin - Ikazuchi - Little Assassin
Footsoldiers: Trilobite Magia - Dodo Magia Chick - Battle Magia
Monsters: Berotha Magia - Kuehne Magia - Ekal Magia - Neohi Magia - Onycho Magia - Vicarya Magia - Gaeru Magia - Mammoth Magia - Dodo Magia - Arsino Magia
Other Villains:
Finis - Will
Gai Amatsu
ZAIA Spec Representatives: Rentaro Tachibana - Tatsumi Arayashiki - Naoto Ichimori - Takeshi Homura - Masamitsu Yudo
Other: Daiki Kyogoku
A.I.M.S.: Eida - Ono - Degawa - Shida - Eifuku - Ito
Monsters: Crushing Buffalo Raider - Splashing Whale Raider - Dynamaiting Lion Raider - Storming Penguin Raider - Scouting Panda Raider - Fighting Jackal Raider
Footsoldiers: Invading Horseshoe Crab Raiders
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