This is a partial character sheet for Kamen Rider Zero-One. Visit here for the main character index. Subjective trope and audience reactions should go on the YMMV page.
This page details tropes for Gai Amatsu from Kamen Rider Zero-One.
Note: Unmarked spoilers ahead. If you're starting the series, do not read this page!
Gai Amatsu/Kamen Rider Thouser/Kamen Rider Thousand Ark
Portrayed by: Nachi Sakuragi (live), Yuji Nakata (suit), Eitoku (suit) (episodes 17-35, Kamen Rider Genms-The Presidents-), Hirotsugu Mori (Kamen Rider Genms-Smart Brain and the 1000% Crisis, Kamen Rider Outsiders)
Young Gai Portrayed by: Seiru
CEO of ZAIA Enterprise Japan
Gai as a child
- "This is going according to my scenario. 100%... no, 1,000%."
Yua's superior and the enigmatic CEO of ZAIA Enterprise Japan. He provides Yua new Progrise Keys for her and Fuwa to use. He is later removed as ZAIA Japan's CEO for repeated failures in regards to the Ark and replaced by Williamson Yotagaki.
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General Tropes
- 0% Approval Rating: While Gai may be a Villain with Good Publicity, none of the main characters like him regardless of what side they're on. And it's not just the main characters, either. As it turns out, he's had 1,843 complaints made against him in regards to his actions and behavior.
- 20% More Awesome: He likes to use percentages for things that aren't easily measured in numbers. This is also usually in contexts for which a number above 100% wouldn't make any sense at all, such as saying something is going 1000% to plan, or insisting that Tatsumi should be 1000% sure of victory. He's so in love with this trope that when he says something is 100% according to plan, it draws a suspicious look from Yua.
- Abusive Parents: #38 reveals Gai had a Fantasy-Forbidding Father who expects him to score an impossible 1000% in school, and would punish him for performing not up to expectations. It gets to the point where his father treats a 99% as if it were The B Grade and scolds Gai out for "wasting too much time" with his robot dog Thouser. This lead to Gai returning Thouser to Hiden Intelligence, whilst believing he has no one else -- human nor A.I. -- but himself to rely on to obtain that 1000% his father desperately expects of him.
- All for Nothing:
- Since Korenosuke patented all Humagears and Zero-One-related technology under his own name rather than his company's, the entire Workplace Competition arc ultimately amounted to Gai buying out a shell corporation. Making matters worse for him is that even with his workaround of recalling Humagears, he's still met with heavy resistance from the public. The only valuable thing that he got was the President's seat itself, which he clings to for an entirely different reason: Hiden Intelligence made his robot dog Thouser.
- Gai manages to delete all the evidence that Shesta collected of his misdeeds, but mere seconds later he's goaded into attacking untransformed civilians while being recorded, creating fresh grounds to call for his dismissal.
- Gai built a new company from scratch after the destruction of ZAIA Enterprise's Japan branch building. He had gambled to his life's work in a duel against Kuroto Dan and lost, leaving him unemployed again. Even so, that didn't bother him at all since he is more concerned about the threat of Zein.
- Arch-Enemy: Gai considers Aruto this as a proxy for his vendetta against Korenosuke, and by the end of the Workplace Competition arc, the feeling is mutual.
- Armor-Piercing Response: Played for Laughs when Gai mentions to Aruto that thanks to Aruto's actions, the sales of the new ZAIA Spec have gone up 724% from what was previously projected. Aruto mocks Gai for this number not being 1000%, a fact which actually irritates Gai enough to prompt a death glare.
- Arms Dealer: Gai aims to weaponize and sell Kamen Rider technology, and buys out Hiden Intelligence in part to gain a monopoly on that tech.
- Arson, Murder, and Jaywalking: In #37, a list of Gai's crimes have been found, and one of the crimes includes ābuying needless amounts of expensive teaā.
- Audience Surrogate: With the advent of Zein, Gai acts as an observant in the conflict between good and evil, represented through the former and Ark. It is shown that he himself is a firm believer of the Balance Between Good and Evil among Kamen Riders; and knows that a world without malice would mean that mankind cannot thrive without something to struggle against. He even speculates that Zein seeks to bring eternal peace and order to the world, but also needed to subjugate humans to pacify their worst impulses because of their capacity for evil.
- The Bad Guy Wins: Both the first and second arcs end with Gai having succeeded in everything he set out to do during them until the opening of the third arc reveals that all of it was for a Meaningless Villain Victory.
- Berserk Button: Fitting his Control Freak nature, Gai really dislikes being defied, especially by his subordinates or opponents that he perceives as being weaker than him.
- Big Bad Ensemble: Shares the role of Arc Villain with the Ark Satellite and Naki in the Hiden Intelligence vs. ZAIA Enterprise Arc. Gai is responsible for ZAIA's buyout of Hiden and is the one driving most of the plot as the central antagonist, but he is not the one creating the Raiders that have started to crop up and interfere in the Workplace Competition or the one hacking HumaGears remotely to turn them into Ark Magia. Except he is behind the Raiders — with Naki working for him. It is still an ensemble with him and the Ark.
- Big Damn Heroes: In #38, when Ark-Zero is about to deliver the finishing blow to Aruto, Gai arrives just in time to deflect the attack and proceeds to back Aruto up.
- Big Ego, Hidden Depths: Gai comes off as a serious Jerkass with a major It's All About Me, Control Freak complex and all around terrible person - but deep beneath that despicable attitude lies a man with some very serious self-esteem issues.
- Bitch in Sheep's Clothing: In public, he acts like a visionary executive who wants to advance humanity. Behind closed doors, he's a smug asshole who only cares about feeding his own ego.
- Blood Knight: He has no qualms in using a ZetsumeRiser to force HumaGears to turn into Magia, just for an excuse to transform and off them as Thouser. He even challenges Zero-One MetalCluster Hopper in battle during his first rampage to test the extent of the Ark's power, only to be swiftly overpowered and defeated.
- Breaking Speech: Gives one to Tatsumi, telling him that his failure will ensure humanity becomes obsolete and face extinction. Tatsumi doesnāt take it well.
- Broken Pedestal: Korenosuke Hiden was his idol in the A.I. industry. However due to their conflicting views on how A.I. technology should be used, with Korenosuke refusing to collaborate with ZAIA as a result, as well as having his grandson named as his Unexpected Successor, Gai makes it part of his vendetta to take over and surpass everything Korenosuke left behind, which includes turning his beloved HumaGears into Magia while framing Hiden Intelligence up for a takeover bid, as well as creating his own Kamen Rider to outperform Zero-One in all aspects.
- Butt-Monkey: Ever since the third arc started, Gai has been hit by a series of failures and humiliation that he seems to have no answer for.
- Can't Take Criticism: Gai's response to Match describing him as a self-centered, arrogant narcissist? Nonchantly stating that he knew HumaGears were worthless in the matchmaking business.
- Character Development: Gai starts off the show's Hate Sink; a greedy, ruthless sociopath whose only motivation is tearing others down and profiting from the wreckage. After a Meaningless Villain Victory at the end of the Competition Arc and scores of one-sided losses chunking his advantage over everyone else, Gai's flawed idea of perfectionism is shattered wholesale; allowing him to finally open up to Ai-Chan about his Dark and Troubled Past and acknowledge what utter human garbage he's been. The Genms Specials make clear that his HeelāFace Turn has stuck despite his colleagues understandably-icy reception to it. While he remains an Unscrupulous Hero at-best, he's gained a fledgling conscience; more-than-willing to link up with The Ark to combat the impending threat of Knight Templar A.I. Zein. This declaration is enough to make The Ark do a Double Take.
- The Chessmaster: Gai is an excellent long term planner, and set in motion the events of the series 12 years ago as part of a plan spanning over a decade to buy out Hiden. Fittingly enough, Gai spends most of the show's first quarter sitting in front of a chessboard. That is also how he is introduced in the opening.
- Clothing Damage: His clothes are notably tattered when he is defeated by the main characters. At one point he was stripped to nothing but boxer briefs courtesy of Naki giving him a personal "message".
- Combat and Support: In the latter half of the series, where he finds himself fully overwhelmed by Metal Cluster Hopper, his standard tactic is to be supported by two Raiders who provide diversionary tactics while he engages Zero One. It's a practice with mixed success as it takes everything he has to damage Zero One and with the advent of Jin Burning Falcon and Vulcan Rampage Gatling, it's frequently a case where he finds Zero One taking out the Raiders while he has the undivided attention of one of the other riders capable of handing him his ass.
- Cold-Blooded Torture: Tortures Fuwa using his AI chip in #29 as a way of demonstrating his hold over him.
- Composite Character: Gai combines traits of both Kuroto and Masamune Dan from Kamen Rider Ex-Aid. Like Kuroto, Gai provides many of the Riders with their equipment to further his own ends. Like Masamune, he manages to maintain being a Villain with Good Publicity despite marketing a highly dangerous and destructive product and manages to temporarily turn some formerly good Riders to his side through a combination of mundane methods and mind control. Like both, he's a Control Freak whose affable facade crumbles into a violent madman the moment he doesn't get his way, and a deeply untalented fighter who has what would be a Story-Breaker Power if it was in the hands of someone who could use it wisely.
- Control Freak: It is eventually revealed that Gai uses his technology to control his subordinates, his main go-to being inflicting pain to keep his subordinates in line, and for one unfortunate Rider, straight out Mind Control on top of it.
- Corrupt Corporate Executive: In contrast to Aruto and Korenosuke Hiden, Gai is basically Greed embodied. He is out to acquire Hiden and boost ZAIA's sales and is willing to utilize underhanded tactics to do so.
- Curb-Stomp Battle: His first few encounters see Gai dish these out, demonstrating the enormous power advantage that his suit has over everyone else's. Once the other Riders get used to fighting him and gain suits more equal to his in power, though, Gai starts receiving curbstomps regularly.
- Dark and Troubled Past: As shown in #38, Gai's father only expected the best out of him, at one point demanding an impossible 1000% on his schoolwork. Years of this along with having no actual outlet besides himself (and Thouser, until the dog was shut away) clearly contributed to how he is today.
- Demoted to Dragon: Essentially what his new position in the Thouser Department is for: To become Thouser and do whatever he is told.
- Didn't See That Coming: Gai makes a habit of seeing his opponents as idiots, leading him to be caught off-guard whenever they do something that isn't according to his script. Most often, this consists of handing his opponent a power-up and then being surprised when they turn it against him. The Raiders, however, are not this, as he was behind them all along with the sole exception of Scouting Panda. His biggest failure of foresight is not checking who owns the patents for Hiden Intelligence's technology.
- Didn't Think This Through: For all of his long-awaited schemes coming into fruition, the third arc of the show exposes three major problems with what Gai had in mind:
- Gai never actually checked the patents for Hiden Intelligence's technology to see who they were registered to. If he had, he would have known that his entire takeover scheme would be all for naught the moment Aruto quit the company. Everything he was after in the takeover remains in Aruto's possession.
- Thanks to his Fantastic Racism clouding his business savvy, Gai has completely ignored the fact that what he wants to do is get rid of an entirely effective and functional workforce that fill in positions human beings are just not capable of substituting in a feasible or even efficient way. When he takes over Hiden Intelligence and recalls all Humagears, he attempts to provide the ZAIASPEC to customers as an alternative, however, this instead allows Aruto's new company to benefit from high-profile customers that want support for the Humagears that have been made an essential part of their companies and could not be made up for by the ZAIA Spec.
- And then there's the matter of sticking Naki's AI on a chip to implant into an A.I.M.S. officer. Not only do they actively rebel and take a new body, but Naki has an intimate understanding of how ZAIA's tech works. Naturally, they exploit this and crack ZAIA's networks open, allowing Ark to seize control of both the ZAIA Spec users and Naki themself a small army of A.I.M.S. personnel.
- Dirty Coward: He can enjoy demolishing his foes only thanks to the technological advantage of his suit and every underhanded tactic in the book. Deprived of that, he has no other option than to scuttle away in anger or as #33 shows, in fear.
- Dissonant Serenity: He generally acts as if the events of the show are just a play he is directing, no matter how dangerous they are. He admits to having caused the Ark to become an enemy of humanity without even changing his usual demeanor. Dude's messed up.
- Easily Forgiven: Zigzagged. After his turn in the Ark-Zero Arc, the other Riders certainly haven't forgiven him for what he's done, but they are at least willing to work with him. And they never actually try to hold Gai accountable for his crimes, even after he's lost his position and power as CEO of ZAIA.
- Enemy Mine: Gai attempts to invoke this in the Genms and Outsiders specials, trying to rally Kuroto Dan and other dark factions like Smart Brain against Zein; even willing to collaborate with The Ark to do so. They completely disregard the notion of unifying in favor of pecking at each other.
- Engineered Heroics: His use of Thouser is partly to improve his own image by taking down "rogue" Humagears. This is despite the fact that as the Ark's programmer, he is responsible for the Magia.
- Even Evil Has Standards: Gai declares his intent to prove ZAIA's superiority to Hiden Intelligence fair and square, even threatening to sue his own competitors if he catches them cheating. He's lying through his teeth, and rigs the contest at every turn by sending Naki to create the Raiders. For the final round of the contest, he abandons all pretense of playing fair and picks a contest where he's allowed to have a corrupt politician be his champion while Aruto has to settle for a rapper due to laws forbidding HumaGear politicians. Then on top of that, Gai astroturfs his way to victory by seeding the crowds with ZAIA employees.
- Played for Laughs in regards to his ambitions compared to Kuroto Dan's. Even at his worst, Gai never actually had any real delusions of godhood like Kuroto did, so he honestly has no idea what the latter is talking about.
- Evil Counterpart: To the entire Hiden family. Both Gai and Aruto are the Presidents of their own companies, but Gai represents the exact opposite of the ideals Aruto has. Whereas Aruto is an Honest Corporate Executive who fights for the sake of co-existence between HumaGears and humanity, Gai is a Corrupt Corporate Executive who poses as a human supremacist, but really cares for nothing but himself. Where Korenosuke was a good father whose children want to build on his vision, Gai is an abusive father whose mistreatment of his child sends echoes of that same mistreatment across multiple generations.
- Evil Is Petty: Gai stands out among Rider villains for being one of the very few who doesn't want to take over or destroy the world. His goal is simply wealth, power, and satiating his ego.
- Evil Versus Evil: Although Gai created MetsubouJinrai.net, all of its members hate him just as much as everyone else does. Gai is such a monster that he manages to be the one who's Eviler than Thou, making MetsubouJinrai.net come out looking like the more heroic party.
- Fatal Flaw: A combination of Greed and Pride. Gai risks a twelve-year scheme falling apart by giving Hiden Intelligence a chance to avoid their buyout, purely because the spectacle of the contest will improve the sales of ZAIA products. Even when he wins, he assumes that Aruto's an idiot and won't have any contingency plan, while he never would have enacted the scheme in the first place if he'd bothered looking up the relevant patents. In general, his scheme relies on thinking he's always going to be one step ahead of the monster he's created.
- His Control Freak nature also serves as one. Gai has to be in control of the situation and the people around him. When his control breaks in the third arc, it marks the start of his Villainous Breakdown.
- Fantastic Racism: Deconstructed. He is much worse than the likes of Isamu and Yua, as his ambition is to shut down all HumaGears due to his petty hatred toward his former idol Korenosuke Hiden. However, Gai's attitude toward HumaGears causes him to downplay and even outright dismiss their value to society as a whole, resulting in him not factoring in that many people in high-profile positions are definitely adverse to the very idea of replacing HumaGears due to how beneficially remunerative and practical they have proven to be in their particular area of business. Later on, it is revealed that he himself doesn't care about humanity, but simply sees people as tools, which in turn results in him having a personal hand in creating his biggest threats.
- Faux Affably Evil: As much of a Jerkass as he is, Gai is good at acting amicable when the cameras are on him (it's part of why he is a Villain with Good Publicity) and in most of his media appearances he comes off as polite, if a little smug.
- Flanderization: Goes through this multiple times in the series. His early appearances depicted him as someone who, while corrupt, was a pro-human Visionary Villain not without principles, even agreeing to redo a round in the Workplace Competition because his contestant cheated and acknowledging the benefits of AI at several points. Midway through the Workplace arc however, Gai suddenly becomes a virulent AI hater and human supremacist who finds a new way to be cruel to Humagears each episode. From there, his personality further flattens into a typical greedy executive who doesn't even believe the pro-human rhetoric he espouses and is happy to throw his own customers under the bus just to make a quick buck. Then it turns out Gai's whole reason for being evil was because his dad told him to study more and play with his robot dog less, and within the span of 10 minutes he develops from being a cold-hearted sociopath to a Robot Dog lover with some smug and arrogant tendencies.
- Foil: To Jun Fukuzoe. Both dislike Aruto because he gained the position of President through nepotism, and seek to claim it for themselves. Where Jun genuinely cares about Hiden Intelligence, and comes around to Aruto's side once he sees how hard Aruto works to protect the company, Gai cares about nothing but himself.
- The Friend Nobody Likes: Even after he joins the heroes, Gai is barely tolerated by the others. When he offers Yua, Isamu, Horobi and Jin employment in the Thouser Division (after Yua points out that Fuwa doesn't have a job anymore), none of them hesitate to tell him "no thanks". If the Ark wasn't so dangerous a common foe, the other characters wouldn't give Gai the time of day.
- From Nobody to Nightmare: Gai's horrible childhood would mold him into the amoral and domineering businessman that we know in the present as an adult.
- Goofy Print Underwear: Wears ZAIA brand underwear.
- Greater-Scope Villain: Gai is the man responsible for shaping the tragedy that molded Aruto and Isamu into who they are now, as well as the man responsible behind the rise of MetsubouJinrai.net by corrupting the Ark. When pointed out, Gai states that it was the Ark who decided it should destroy humanity after being shown how low they could sink.
- This extends to him being the true villain of Kamen Rider Zero-One: REALĆTIME as well, even if he's no longer a villain, since S only became a villain because of a tragedy he suffered in the Daybreak Town Incident.
- Ironically, him being behind the Ark also makes him this to the Genms ~The Presidents~ special since the Ark is responsible for Kuroto's return, even though Gai is the protagonist in that special.
- The only works that avert this are the Zero-One Others movies as the Big Bad there is Lyon Arkland, Gai's boss.
- Greed: At the end of the day, Gai just wants to make more money and doesn't believe in his Humanity Is Superior philosophy at all, given how he's perfectly willing to throw his fellow humans under the bus to boost the sales of his products.
- Hate Sink: Gai has almost no redeeming qualities whatsoever, making him far worse than Horobi in terms of depravity. He is directly responsible for the Daybreak Incident that killed hundreds of humans, seeks to turn Kamen Riders into super-soldiers, and does everything in his power to destroy Hiden Intelligence seemingly out of pure spite towards Korenosuke for not agreeing with him and HumaGears. Even outside of that, Gai is thoroughly unpleasant to be around. He acts condescending and demeaning towards everyone he meets, pins the blame on the heroes for disasters he himself caused, and takes every available opportunity he can to torment Aruto by destroying his creations. Notably, actor Nachi Sakuragi has said in interviews that not only does he deliberately makes Gai as despicable via his acting, his goal is to make Gai even more hated than Masato Kusaka, who is one of if not the single biggest Hate Sink in the entire Kamen Rider franchise (other candidates being outright villains like Takeshi Asakura or Tenjuro Banno). Gai is such a hate sink that it actually becomes a plot point: the idea of someone as despicable as Gai would legitimately join the heroes was so implausible that even the superintelligent Ark was completely blindsided by it, which gave the heroes the chance to take their first true victory over the Ark.
- Hated by All: Gai, rather impressively, managed to give almost every other character, hero or villain, personal reasons to hate his guts over the course of the series. Even Aruto can't stand him.
- Heads I Win, Tails You Lose: This is ultimately his plan with the Five-Stage Workplace Competition against Hiden Intelligence. He sets up the contest to ensure that many of the HumaGears involved will be bullied into turning into Magia, allowing him to destroy Hiden Intelligence's reputation regardless of the outcome. He then makes the final round a political contest, ensuring that there's nothing Aruto can do to win it, as HumaGears can't hold public office. Inverted as it turns out thanks to Korenosuke patenting all the technology he actually wanted from acquiring Hiden Intelligence in his family name rather than the company. Thus, win or lose, Gai would've never gotten what he wanted anyway.
- HeelāFace Turn: Pulls one in #38, thanks to Aruto and Ai-chan. That said, some haven't quite forgiven him for his past actions.
- Hidden Agenda Villain: His plan in the second arc seems to just be to acquire Hiden and boost ZAIA's sales, though it is alluded to several times that Gai has something much grander in mind.
- Hidden Depths:
- As greedy as the man is, he is not without a sense of honor: it does say something about Gai's character when he offers Aruto a chance to avoid the buyout instead of just taking Hiden Intelligence right then and there. Unfortunately, this turns out to be a lie, as he was rigging the competition from the very beginning by ordering Naki to hand out RaidRisers: no matter who wins, Gai either obtains Hiden Intelligence or the repeated showcasing of how "easily" HumaGears can become Magia will ruin Hiden Intelligence's reputation.
- In #18, Is analyzes his personal history:N.E. 1974: Born on 10 October.
N.E. 1991: 17 years old, Thousand Network ā¦
N.E. 1992: 18 years old, Stanford Graduate School of Business ā¦ (MBA Program)
N.E. 1996: 22 years old, ZAIA Enterprise AI Team.
N.E. 2007: Moved to ZAIA Enterprise Japan. As the Project Manager, participated in the ā¦ project which involves a number of technology companies, including Hiden Intelligence.
N.E. 2009: Assigned as the President. Currently gathering attention from the world as ācharismatic presidentā ā¦ - #25 reveals he is looking to find someone to marry.
- Despite being one of the Big Bads of the second arc and otherwise condescending attitude towards Aruto, someone who became a Kamen Rider to help Humagear and humans co-exist, he has a surprising view towards the overall role of the Kamen Riders as a whole:"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!"
- #38 shows that he's an emotional wreck, whom since childhood desired some sort of recognition for his efforts and a companion that he could open up to. Fast-forward to today, and he didn't receive any of that. What's worse, is that his feelings worsened as time went on, and had basically become a cry for help.
- Hoist by His Own Petard: Gai creates no less than three powerful Progrise Keys that end up in the hands of someone who wants to kick his ass, and two of those times involve him forcing the upgrade on his opponent because he thinks he'll be able to control them. Even after taking over Hiden Intelligence he still falls into this trap: his HumaGear recall simply gives Hiden Manufacturing a whole clientele to reach out to and cultivate. It gets to a head by the very end, when Ark, the very system he corrupted for his overall plan, got so powerful to a point where his ThousanDriver was destroyed, permanently defeating Thouser for the series...at least until the ending credits where it's shown that he has rebuilt his Transformation Trinket.
- Humanity Is Superior: He professes to be a human supremacist, claiming machines like HumaGears can't keep up with human evolution. Ironically, his profit-driven mindset is more cold and data-focused than any HumaGear's, his suit is designed to already be "perfect"note , and he shows no signs of improving his skills through experience, making him the only Rider who isn't evolving. Shortly before forcing the MetalCluster Hopper Progrise Key upon Aruto, however, Gai professes a rather darker view of humanity, claiming that the Ark's judgment is exactly what mankind deserves.
- Eventually his true view for humanity is revealed, at is more about using them as tools for his own gain.
- Humans Are the Real Monsters: Gai is eventually outed as The Man Behind the Man to MetsubouJinrai.net and the one responsible for the formation, which he ironically caused by invoking this trope on the Ark.
- Humiliation Conga: Gai has routinely been on the receiving end of an ass kicking, usually by someone with a power-up that he himself has created. Also his plans to own the Humagear patent went down the drain when he found out Aruto inherited it and all other related patents due his grandfather being one step ahead, and making it so in his will.
- Hypocrite: As noted in Humanity Is Superior above, Gai's talk of human evolution is contrasted against Gai himself being a parasite whose only growth comes from stealing the powers of the more talented people around him.
- I Control My Minions Through...: While a good number of his henchmen and associates follow him willingly, for some of his more higher ranked assets, like Yua, Gai uses AI chips implanted in their heads to Mind Control them to ensure their loyalty.
- I Just Want to Have Friends: Deep, deep down behind that cold, unlikable exterior, is a longing desire from his childhood for a friend - someone that he could open up to. Thouser was the only thing that he could consider a friend.
- Insufferable Genius: He loves to flaunt his superior intellect.
- Invincible Villain: In the second arc. While the heroes become able to physically outmatch him, they haven't managed to deal with his resources and aren't able to get lasting wins against him. He loses some invincibility in the third arc; when his Manipulative Bastard behavior stops working, and he fails to acquire Zea, the Zero-One Driver, and the HumaGear patents, his enemies start gaining ground against him.
- It's All About Me: Despite coming off as charming and savvy, Gai's only concern at the end of the day is his agenda. Humagears, his competition representatives, and even his right-hand Yua are nothing more than pawns to him, and he makes no effort to hide it.
- Jerkass: Even when he is not being villainous, Gai is still incredibly insufferable and takes every opportunity he can to talk down to Aruto.
- Jerk with a Heart of Jerk: Gai takes every available opportunity to demean Aruto whenever the latter feels down from something related to the competition, outwardly protests against cheating while rigging the contest at every turn, and viciously slaughters HumaGears whenever given the opportunity. Any time he's shown to have any sort of redeeming quality, it's later revealed to be a lie.
- Jerk with a Heart of Gold: Downplayed, but it turns out there is still someone that he actually cares about other than himself, even after everything he went on to do. His childhood robot dog, Thouser.
- Karmic Butt-Monkey: During the third arc Gai has been hit with series of humiliation and defeat in the hands of Aruto, Yua and MetsubouJinrai.net and you won't feel sorry for all the troubles he had been through, considering his actions during the second arc.
- Karma Houdini: While he loses his position as CEO in the end, and gets some well-deserved beatdowns as well, Gai is never held fully accountable for his actions in corrupting the Ark and setting off the Daybreak Incident, or his numerous other crimes in the series. In fact, he arguably ends the series in a better place than Aruto, seemingly content with his now position now that he has dozens of Thousers to accompany him. As of the end of Zero-One Others, he's probably come out the best of the main characters. All of Metsuboujinrai.net is Killed Off for Real, Fuwa is possibly dead and Yua has lost her ability to transform and her best friend (possibly). Gai meanwhile survives ZAIA Japan's destruction and gets back his Thousan-Driver after Lyon's demise.
- Kick the Dog: It is almost Once an Episode for him. Whether it is forcing Aruto's Humagear to turn into Magia and destroying them out of spite, to torturing Fuwa with his AI chip, to trying to scrap Is because of her value to Aruto, Gai always finds a new way to be nothing but an insufferable man he is.
- Lack of Empathy: The only feelings he will ever care for are his own. He doesn't even flinch when he sees someone suffering in front him and is perfectly fine with torturing others just to make a point.
- Laser-Guided Karma: The same method he used to sow chaos in ousting Aruto from HIDEN Intelligence by showcasing HumaGears going berserk; he is finally brought down by his record of abuse of power via going berserk to his own employees recorded and forwarded to ZAIA by Shesta, a HumaGear he very despised.
- Light Is Not Good: He wears a white suit and dons gold and silver armor as Thouser, but he is anything but a good guy.
- List of Transgressions: Hoooo boy, he has a long one. Specifically, one consisting of 1,843 complaints that were made against him. Some translated entries include:
- Age spoofing
- Buying unnecessarily large quantities of expensive tea
- Faking reasons of absence
- Illegal auction bidding
- Illicit sales
- Misappropriation of company finances for personal benefit (i.e trips to beauty salons and hot springs, haircuts, etc.)
- Plagiarizing technology from other companies
- Possession of a fake bank account
- Sexual/Moral harassment
- Tax evasion
- and many, many more complaints!
- The Man Behind the Man: Project Thouser reveals that he was backing MetsubouJinrai.net, through Naki, along with A.I.M.S., being the one responsible for giving them the first 8 Zetsumerise Keys and later Jin's ForceRiser. Once MetsubouJinrai.net is defeated, Gai openly admits to being personally responsible for the Ark's belief that Humans Are Bastards, and thus the Daybreak Incident. He later turns out to be behind Naki and the Raiders as well.
- Manipulative Bastard: He engineered a panic over berserk HumaGears by having Yua tamper with Little Assassin's LED earpieces to make it seem like any HumaGear can go berserk at any time for the express purpose of putting Hiden Intelligence in such a bad place that they'd have no choice but to allow him to perform a buyout and hostile takeover. He also destroys evidence that prove his company's or his own wrongdoings. This ultimately extends to the entirety of the buyout competition, as he was the one setting up distribution of the RaidRisers to begin with and lied about it until he had literally no other choice.
- Meaningful Name: His first name Gai (å, Gai) is a numeral character which means 10^20note in Japanese.
- "Thouser" sounds like "Thousand", calling to mind his motif.
- It's eventually revealed that Kamen Rider Thouser takes its name from the robot dog he owned as a child, which his Jerkass Education Papa father ordered him to get rid of since it "distracted" him from achieving his full potential.
- Meaningless Villain Victory: Gai manages to complete his hostile takeover of Hiden Intelligence, which should mean he now has all ownership and control of its technology, including the Zero-One Driver, Zea and HumaGear tech in general. Unfortunately for him, all of his hard work turns out to be for naught as Korenosuke never patented the tech under Hiden Intelligence. He patented it under the Hiden family name and gave all the patents to Aruto in his will. As a result, Gai was not happy to learn about this.
- Meet the New Boss: Pun aside, he's essentially a repeat of Kuroto Dan from Yuya Takahashi's previous entry in the franchise, only replacing Kuroto's exaggerated hamminess with a sneering Jerkass personality. Like Kuroto, Gai is a Corrupt Corporate Executive who manipulates both the heroes and villains to further his goals, has several quirks, and an extremely petty attitude. He even follows a similar arc to Kuroto, starting off a cruel villain before becoming more humanized and joining the heroic side as The Friend Nobody Likes. Although unlike Kuroto, Gai doesn't go back to being a villain once the dust settles.
- Morality Pet: Thouser, a robot dog from his childhood made by Hiden Intelligence, which he shut away during his Start of Darkness enforced onto him by his abusive father. He eventually relents and breaks down in tears after reuniting with an upgraded Thouser specially made for him.
- Never My Fault: When Aruto confronts him over his programming of the Ark and by proxy, his responsibility for the MetsubouJinrai.net incident and all the deaths that resulted from their activity, he simply says that he's not responsible since the Ark made the decision to become genocidal after being swamped in data of human malice.
- Not So Stoic:
- One of the few ways to break his smugness for a moment is to point out his real age or state that he is, in fact, a narcissistic prick. Not even a possible death at the hands of MetalCluster Hopper actually fazes him that much.
- He actively shouts at Yua for refusing to destroy G-Pen Morifude in #31, and at Aruto once he and Jin team up to take him down when he tried destroying Hiden Manufacturing.
- He flips out again in 35 when Horobi beats him, knocking away the AIMS troops trying to help him up.
- Older Than They Look: Gai looks (and claims to be) "eternally 24". A quick scan from Is reveals he is 45. Eyebrow raising as that is, it is compounded by the fact that based on a photograph of himself with Aruto's grandfather, he hasn't aged a day in at least 12 years. #37 goes so far as to suggest Gai's insistence runs so deep that he's received numerous complaints about downright committing age fraud, presumably in things like official documents.
- Only Sane Man: In the Genms and Outsiders specials, at least. He's the only one that recognizes Zein as the impending Hero Antagonist that it is and tries his best to get the various Mega Corps to work together to prepare for it. They decide to ignore him and continue sniping at each other instead.
- The Perfectionist: Basically, Gai is built on this trope, as anything less than 1000% is unacceptable.
- Pet the Dog: Literally, in fact. When he's reunited with Thouser, now with a new body, he finally breaks down in tears of joy.
- In the Presidents special he decides to take a page from Aruto's book and designs himself a Huma Gear secretary that he names Rin. Despite his previous hostility against Huma Gear's Gai very quickly becomes attached and protective of her and fights Kuroto for her sake only a few minutes after she's first activated.
- Playing Both Sides: The benefactor of AIMS and The Man Behind the Man to MetsubouJinrai.net, who he isn't above using to sink Hiden's stocks.
- The Power of Hate: Much like the Raiders his ZAIASPEC enables, Gai is motivated by a cold and petty hatred for his former idol Korenosuke Hiden due to being snubbed out of a collaboration between ZAIA and Hiden Intelligence because of their conflicting views on A.I.
- Pragmatic Villainy: Gai wonāt allow his competition representatives to cheat in ways that can be traced back to him. If it can't be traced back, though, then all bets are off.
- Properly Paranoid: The introduction of Zein and its objectives of a malice-free world has Gai becoming cautious of its influence upon the world, to the point he believes that Zein seeks to eradicate mankind to establish a utopia of eternal benevolence and order. Most of his speculations about Zein are, if not all, proven true, further highlighting its authoritarian tendencies, right from indiscriminately labeling a reformed Megid as "evil" despite having redeemed himself to executing a certain Mad Scientist with extreme prejudice after beating him within an inch of his life.
- Reformed, but Rejected: Even after his HeelāFace Turn, Aruto and the other Riders don't accept him, though they are at least willing to work with him.
- Shadow Archetype: Gai is basically what Aruto could be like not only if the latter allowed his position as CEO of Hiden Intelligence to go over his head, but have the willingness to resort to morally questionable, and if not all, criminally underhanded methods to preserve his company.
- "Shaggy Dog" Story: He starts his own tech company after the destruction of ZAIA Japan branch. When he revives Kuroto Dan as a Humagear, he has to gamble the ownership of Thouser-Intellion in a fight against the latter and he ultimately lost.
- Smug Snake: Gai is smugly convinced of his own superiority and genius, but this also leads him to underestimate his enemies, which hinders the effectiveness of his plans. The entire idea of the Workplace Competition was meant to let him crush Hiden Intelligence and HumaGears, but even though he won his overconfidence led him to literally give his enemies the power they needed to fight him evenly.
- The Sociopath: Gai is the type of person whose expression of genuine happiness mainly come from whenever he benefits from something, has little to zero consideration of others, even those that work closely with him, has no problem being underhanded and manipulative towards heroes and other villains alike, and was the instigator of the series' events that he never takes responsibility or shows remorse for, all while having a decent public image.
- Start My Own: After ZAIA Japan collapses in the MetsubouJinrai film, Gai moves to start his own tech company - Thouser-Intellion.
- The Stoic: Gai's attitude throughout the first quarter is never anything but calm and collected. Even when Aruto gains what Gai estimates to be an increase in strength of 500% through the Shining Hopper Progrise Key, all Gai has to say in response is that he can't wait to see Aruto fight Thouser. Considering he is Thouser, this takes on another meaning.
- Stupid Evil: He's rather prone to bouts of this.
- His plan in the Workplace arc to use Naki to possess Fuwa and make him hand out Raidrisers, in order to use the Workplace Competition as a testing ground for them. Not only did he not need to do it (he could have tested them in secret someplace else), all it did was lead to his crimes being exposed.
- Him giving Naki access to ZAIA's network and planning to have all the ZAIA Spec wearers go berserk, in order to boost up sales of the Raidriser, is also this. Apparently Gai was so focused on making the sales for the Raidriser go up he forgot about making sure his other product (which he spent the entire Workplace arc trying to market) didn't go down in sales.
- Take Over the World: On the eve of his triumph, he declares his intent to dominate the world with ZAIA's technology.
- Tea Is Classy: Gai favors drinking tea as part of his wealthy tastes (or as wealthy as taking money from the corporate budget to finance his habit can be.)
- Teen Genius: In his younger years, Gai founded the Thouser Network at the age of 17, and had an MBA degree at Stanford University a year later. He then joined ZAIA at the age of 22, rising through the ranks of the company until he became president despite his own company having been bought out by ZAIA.
- Teeth-Clenched Teamwork: What his team-up with Aruto against Ark-Zero basically amounts to. He still doesn't accept Aruto, his love for HumaGears, and the way he runs a company, but he still loves Hiden Intelligence. For Gai, that's all that he needs.
- Then Let Me Be Evil: A possible interpretation of his actions in the ZAIA vs Hiden Arc, given his views about how Kamen Riders themselves decided whether or not they will pursue a path to destruction or fight to protect others. If he isn't just saying that to make himself look good, then Gai willingly pursued the path of a villainous Rider if only to prove that Humanity Is Superior. Later it turns out that he really is evil and sees other people more as a means to an end.
- His Dark and Troubled Past with his Education Papa further implies this.
- He does it again after putting on the Ark-Driver Zero in Kamen Rider Genms -Smart Brain and the 1000% Crisis-, where he declares that if it will secure humanity's future, he'll become an incarnation of the Ark to do it.
- Third Act Stupidity: It's right around the third arc that Gai loses his edge and goes from an Invincible Villain to being overshadowed by the return of the Ark.
- Transformation Is a Free Action: Even putting his belt needing two keys to function aside, his transformation sequence is decadently long.
- Trigger Phrase: The words "tool" or "my tool" seem to be one that he uses on Yua to ensure her compliance; when he says it to her in #31, she winces much like Fuwa did under mind control before acknowledging his order. Later appearances show that he's capable of doing this through his ZAIASpecs or remotely as Thouser, so the above just might Gai subtly reminding Yua of her place through her chip.
- Transhuman Treachery: His desire for humans to "evolve" so as to not be made redundant by HumaGears might seem laudable, but his willingness to stomp on both man and machine alike to achieve this most definitely isn't.
- Unscrupulous Hero: Post-HeelāFace Turn, he's this at his most generous. He remains the CEO of a predatory company during the main show and effectively ducks out of the events of Others. During the Genm Specials, he continues to work with the homicidal A.I. that's threatened the world eight times over and decides reviving the equally-homicidal, less-predictable Dan Kuroto to help deal with an impending Knight Templar A.I. is somehow a good idea.
- Verbal Tic: He loves describing things in terms of percentages, with his favorite number of course being 1000%.
- Villain Has a Point: While the show does try to portray him in the wrong, Gai is correct when he points out that Humagears are a liability for how often they get hacked into Magia, especially once it's clear that it can be done remotely.
- Villain in a White Suit: The villainous Corrupt Corporate Executive Gai can always be seen clad in a white suit.
- Villainous Breakdown:
- Starts in #30 when he finds out that no, he doesn't own the technology he was after when he acquired Hiden Intelligence, and kicks into high gear in #31, finally breaking his composure after losing again to Zero-One with the help of Jin. He angrily swears to get back at Aruto before pushing away Eida and Ono who were both trying to help him get back up. It gets even worse in #35 where he loses to Horobi and furiously declares Horobi as absolutely unforgivable.
- First half of #38 is this as it finally comes to head when Jun and Sanzo with help of Shesta threatens to bring all 1,841 complaints to the board meeting; he goes into panic by shutting them out of the lab and desperately deleting all evidence of unethical behavior, then gets angrier when Satellite Zea rejects his request to mass-produce the Raidrisers, Aruto coming in via emergency entrance to help unlock the lab entrance and Jun cancelling the pre-orders of RaidRisers leads to Gai going on the deep end and taking out his rage on both as Thouser. After he's finally stopped, Shesta forwarded footage of attacking the VP as clear abuse of power and Gai becomes utterly depressed over while clinging to the President chair because that's all what he wanted. Ironically, what happens after starts his HeelāFace Turn.
- Villain with Good Publicity: Firmly settles into this role at the end of the Workplace Competition arc, having successfully painted himself and ZAIA as heroes to the public. Presumably it's revoked when Naki hacks the ZAIASPECs en masse and hooks them to Ark to send their users on a rampage in #34.
- #37 doubles down on this by revealing he has a record of 1,834 complaints made against him for a number of legal and HR issues. It's safe to say that Gai isn't popular with anybody at this rate.
- Visionary Villain: Averted. Gai claims to want to see humanity evolve, but he's perfectly willing to throw even the humans who embrace his vision under the bus if it allows him to make more money in some way.
- Walking Spoiler: Gai has his fingers in just about everything that happens in the show, so it's hard to talk about him without spoiling his role in the plot.
- War for Fun and Profit: While it isn't his main goal, Gai isn't above using the MetsubouJinrai.net crisis as an excuse to sell weapons. In #25, he even openly admits that the return of the terrorist group would be good for ZAIA since they could make more money selling weapons to A.I.M.S. #35 showed how flawed this belief is, since it shows that everything Gai sold to A.I.M.S. can be seized by Naki's hacking as easily as the ZAIASPECs when the MetsubouJinrai.net does make its return.
- "Well Done, Son" Guy: He ultimately boils down to this as his motivations are all stemmed from him complying with his abusive father's standards, even if they are ridiculous, to the point of willingly sacrificing his friendship with Thouser to prove that he can achieve the 1000% in life his father wanted.
- Wham Line: #15 puts a new angle on Gai's relationship with MetsubouJinrai.net:Gai: As the Ark guides us, we approach an age of our new mythology. [...] Yes, the mythology of the Kamen Riders.
- You Have Failed Me: As Gai's control of the situation starts to slip, he becomes increasingly brutal towards his own subordinates, eventually escalating to where it's implied that he has the second set of Battle Raiders executed by the third for failing him.
Tropes exclusive to him as Thouser
Tropes exclusive to him as Kamen Rider Thouser:
PerfectRise!
When the five horns cross, the golden soldier Thouser is born.
Presented by ZAIA.
When the five horns cross, the golden soldier Thouser is born.
Presented by ZAIA.
Singurize!
When the five horns cross, the Thousand Ark is born.
Presented by ARK.
When the five horns cross, the Thousand Ark is born.
Presented by ARK.
- Animal Motifs: Comprises of two, which mainly makes up his five horns: His two silver horns are from the Arsinoitherium, an extinct animal that closely resembled a rhino with two big horns, and his three black horns are from the caucasus beetlenote .
- Assist Character: In a similar manner to Horobi, Thouser can summon the Rider Model of the copied Progrise Key in his Thousand Jacker to assist him in battle, such as summoning the Flying Falcon Rider Model to help him fly across the battlefield.
- Bling of War: He is fancy enough to fit his gold-silver-black suit as Thouser.
- Can't Catch Up: Thouser debuts vastly superior to anything before it. Unfortunately, it was designed to only function with its intended keys, meaning that there was no way to modify the base suit beyond its original specifications. In a series themed around technological progression, Thouser sat still believing his early advantage made him invincible. His arrogance and laziness let everyone else advance enough to match or surpass him.
- Crippling Overspecialization: All of Thouser's powers beyond his brute strength are tied up in the Thousand Jacker. If he's disarmed or otherwise unable to use it, all those powers he gathered might as well not exist.
- Crutch Character: He's effectively this trope in Kamen Rider form. Thouser starts the second arc able to thrash every other combatant with little effort, but by the arc's end his lack of growth comes home to roost. Starting from the beginning of the third arc, he's become a glorified jobber. The only times he's a threat after that point are when he has significant backup.
- Dark Is Evil: Subverted. When he was infected by the Bugster Virus in the Kamen Rider Genm special, his suit turned black. Later played straight when he gets access to Thousand-Ark, which has him take the Ark-Driver and insert an unique Progrisekey that resembles the Ark-One Progrisekey that resembles Thouser's head instead, but by that time Gai is already on the side of good, so the "Evil" part is subverted.
- Discard and Draw: Thousand Ark completely discards the ThousanDriver and the Thousand Jacker in favor of the Ark Driver.
- Evil Knockoff: His suit is perfectly identical to Zero-One's in every regard except for the colors and some additional armor laid on top, in a manner reminiscent of the infamous Tian-xiang-er-hao statue
◊. - Evil Sounds Deep: Thouser's belt and Progrise Keys have a substantially deeper and more menacing voice than the usual Keys.
- Finishing Move: Like the other Riders, Thouser has different finishers depending on whether he uses his Driver or a weapon to execute them:
- ThousanDriver: Thousand Destruction: Executed by pressing inward on the Amazing Caucasus Progrise Key.
- Thouser leaps into the air and rapidly delivers several flying kicks with his foot before landing in victory.
- Thouser does a jumping knee strike to lift his opponent in the air and perform a diving stomp.
- Thouser does a spinning back kick along with a sidekick to follow.
- Thouser delivers a backwards kick covered in purple and gold energy.
- Thouser delivers a spinning roundhouse kick covered in gold energy.
- Thousand Jacker: The weapon is capable of performing 3 finishers; Jacking Break note , Hacking Break note , and Thousand Break note .
- Jacking Break (Flying Falcon): After initially drawing energy from the Flying Falcon Progrise Key, he can summon a construct of its Rider Model, either to attack the target or to help him move quickly across the battlefield.
- Jacking Break (Shooting Wolf): After initially drawing energy from the Shooting Wolf Progrise Key, he generates either 1 huge construct or multiple smaller constructs resembling a wolf's head, which he fires at the opponent.
- Jacking Break (Biting Shark): After drawing energy from the Biting Shark Progrise Key, he slashes the opponent with a whip-like chain of energy "shark fins".
- Jacking Break (Punching Kong): After drawing energy from the Punching Kong Progrise Key, he fires a construct of the Knuckle Demolition at the opponent, which, after hitting, splits into multiple Demolitions and repeatedly strikes the opponent.
- Jacking Break (Flaming Tiger): After initially drawing energy from the Flaming Tiger Progrise Key, he coats the Thousand Jacker with fire and launches a flaming slash at his opponent. Alternatively, he can use it to remotely release fire to attack enemies.
- Jacking Break (Shining Assault Hopper): After initially drawing energy from the Shining Assault Hopper Progrise Key, he is able to generate his own purple variant of Assault Hopper's Shine System. Alternatively, he can fire a purple version of the Authorise Buster's Zero-One Dust.
- Jacking Break (Breaking Mammoth): After initially drawing energy from the Authorize Buster's Breaking Mammoth Buster Bomber, he can fire a purple construct of a mammoth's tusk at the opponent.
- Jacking Break (Freezing Bear): After initially drawing energy from Freezing Bear Progrise Key, he creates a construct of its Rider Model, which then rushes toward its opponent and turns into a icicle before impact. Alternatively, he unleashes a wave of ice from his Thousand Jacker, freezing his targets in place.
- Jacking Break (Lightning Hornet): Thouser channels Lightning Hornet's power and fires lightning at his target.
- Jacking Break (Sting Scorpion): After drawing energy from the Sting Scorpion Progrise Key, he fires a yellow and purple construct of the Acid Analyze on a chain at his opponent.
- Jacking Break (Japanese Wolf): After drawing energy from the Japanese Wolf Zetsumurise Key, he pins the Thousand Jacker into the ground and performs a Tiger feint kick, creating a whirlwind of snow to attack multiple opponents.
- Hacking Break (Rushing Cheetah): After inserting the Rushing Cheetah Progrise Key into the Thousand Jacker, Thouser speeds around the target, surrounding them with energy slashes, which all strike at once after a couple of seconds.
- Thousand Break (Lightning Hornet): After inserting the Lightning Hornet Progrise Key into the Thousand Jacker, he delivers powerful strikes with lightning generated from his Thousand Jacker.
- Thousand Break (Dynamiting Lion): After inserting the Dynamiting Lion Progrise Key into the Thousand Jacker, he creates two large Gatling gun constructs to mow down his opponent.
- Thousand Break (Amazing Caucasus): After inserting the Amazing Caucasus Progrise Key into the Thousand Jacker, he spins the Thousand Jacker around, creating constructs of the Rider Models of all the Progrise Keys he's absorbed so far, which then he fires them all at once to overwhelm the opponent.
- Thousand Break (Sting Scorpion): After inserting the Sting Scorpion Key into the Thousand Jacker, Thouser stabs down, launching a purple construct of the Acid Analyze unit on a chain at the opponent. It then stabs its opponent, lifting them up in the air before exploding.
- Ark Driver: Judgement Conclusion: After pressing the Progrisekey once, Thousand Ark attempts to impale his opponent with tendrils from his arm. Key word: attempts. He doesn't get one hit in before Genm uses Pause to avoid his attacks and him retaliating with a Genm Critical Finale on Thousand Ark.
- ThousanDriver: Thousand Destruction: Executed by pressing inward on the Amazing Caucasus Progrise Key.
- Foil: Thousand Ark is this to Ark-One. While Ark-One's main user, Aruto Hiden, was completely consumed by The Power of Hate while using the Ark Driver, Gai Amatsu is completely himself while using it. Lastly, their circumstances of obtaining are different: Aruto obtained it after Is being fatally shot by Horobi and As giving it to him to provoke him on a Roaring Rampage of Revenge that will end in a Robot War, while Gai Amatsu obtained the Ark Driver to secure humanity's future.
- Forgot About His Powers: While Thouser uses Jacking Break at least once in every fight, he often doesn't think to use situational powers that would be effective for the battle he's in, instead defaulting to Shining Assault Hopper because it's the easiest to use.
- Gold-Colored Superiority: Befitting his regal theme, Thouser's suit is primarily golden.
- Gratuitous English: All of his Finishing Move cards are spelled out in English instead of Japanese, to represent ZAIA's multinational reach.
- Head Swap: Thousand-Ark is essentially Ark-One but with Thouser's head instead.
- Irony: He is the only Rider in-series to have his finishers copyrighted, but most of them are actually based on powers he stole from other Riders.
- Linear Warriors, Quadratic Wizards: At first, Thouser held a major Advantage Ball by having a suit with greater physical prowess than the other Riders as well as the use of the Thousand Jacker's Power Copying to add other Riders' powers to his arsenal. However, the other Riders began adapting to and outmatching him, whether through a Next Tier Power-Up (Jin), observational skill (Horobi), natural fighting abilities (Valkyrie) or the combination of raw power and experience (Zero-One, Vulcan). Without an innate special ability of his own, Thouser is only left with the Thousand Jacker to even the field, and Gai wasn't a much of a fighter to begin with, so he never has the chance to make a proper adjustment to the sudden changes.
- Logical Weakness: Thouser's Thousand Jacker works by attacking a Rider, and then absorbing their energy to become stronger. That doesn't mean jack to an opponent who can create shields to keep Thouser's Jacker from absorbing their energy, which MetalCluster Hopper can do. MCH also showed that if Gai is separated from his weapon, he can't use the powers he's stolen.
- He deliberately designed his belt to only work with his original keys. While he was unquestionably the most powerful Rider yet at the time of his introduction, it also put a hard cap on his potential growth and prevented him from using other Progrise Keys with more situationally useful abilities. He's able to get around this to a point using the Thousand Jacker to copy abilities, but its constructs don't match the utility someone capable of transforming with multiple Keys could have.
- And then there's the point made under Villain Forgot to Level Grind below: Gai never bothers to improve his combat skill at all, relying completely on the Thousand Jacker and his suit's strength. So when the others eventually start to get upgrades approaching or surpassing his suit, he has no counter to them and gets rolled over without backup.
- Master of None: Overusing his Power Copying ability slowly turns him into this. Over the course of the show, he gains so many abilities in his roster that having to sort through them all slows him down in battle and his lack of practice with them limits his usage to the most basic applications of each. His overreliance on the flashy powers he steals causes him to neglect his basic melee skills, squandering even the impressive physical combat advantage his suit should give him. His increasingly split focus leaves him so vulnerable that by the latter part of the series Riders that are, on paper, far weaker than him defeat him handily.
- Magically Inept Fighter: Thouser, for all intents and purposes, fits this to a T. His suit has excellent physical statistics, competitive even by the standards of the late portion of the series, but it lacks any natural abilities beyond its basic physical enhancements and durability. His only special ability, sampling and copying other Progrise Keys, is entirely contained in his Thousand Jacker weapon. If he can't use the Thousand Jacker, all he has is basic melee combat while everyone else has at least one inherent superpower.
- Meaningful Name: The name Thouser comes from the word Thousand, a number Gai favors quite a bit for boasts about his company's success rate.
- Mighty Glacier: On paper, Thouser should be a Lightning Bruiser who vastly surpasses everything that came before him in every category: he's faster than Rushing Cheetah, stronger than Assault Wolf, and can out-predict Shining Hopper. In practice, however, Gai's poor reflexes mean that he's even less agile than Assault Wolf. However, his armor is so insanely tough that he's able to easily recover after being pushed back by a high-speed onslaught.
- Nigh-Invulnerability: At the time of his reveal, Thouser is so tough that he can No-Sell anything from the show's previous two Lightning Bruisers. Shining Hopper (who emphasizes the Lightning) can barely make him move and Assault Wolf (who emphasizes the Bruiser) can do little more than make him stumble. Shining Assualt Hopper (who acts as a medium between the two) can fight Thouser relatively more evenly. It takes something as powerful as MetalCluster Hopper to overpower Thouser, and that comes with caveats.
- No-Nonsense Nemesis: Thouser's laser focused during battle, focusing on either eliminating his enemy or clearing his path to his decided target. Due to the sheer power the Thousandriver grants him, doing so is child's play.
- Power Copying: Thouser can use his Thousand Jacker sword like a syringe and steal the powers of an opponent's Progrise Key for himself. This temporarily weakens the power's original user, but even after they've recovered, Thouser retains any powers he previously jacked, allowing him to use them anytime.
- Power Up Letdown: Despite finally updating the outdated Thouser to Thousand Ark he gets crushed by the equally new Gemn Musou.
- Redemption Promotion: A minor example, but turning face gives Thouser some reprieve from his Unskilled, but Strong status, enough so that he and Zero-One are able to overwhelm the previously unstoppable Ark-Zero. This fight stands out as the only defeat that Ark-Zero suffers that doesn't involve Zero-Two.
- Secondary Color Nemesis: Thouser has a regal gold and silver color scheme on the outer layers of his armor, with a more menacing set of black and purple tones on the suit beneath. The combined result is the image of a villain doing everything in his power to look like a hero.
- Spikes of Villainy: The five horns on Thouser's helmet count as this. They are also made to resemble a Cool Crown, fitting for his king-like aesthetics.
- Super Mode: Thousand-Ark, which is essentially Ark-One, but has Thouser's head replacing its head instead.
- Superpower Lottery: Once he's stocked up on every other Rider's powers through various uses of Jacking Break, Thouser has a combination of an enormous physical advantage and the ability to do anything that his rivals can do, sometimes better. As the series went on, the downside of this trope started to rear its ugly head: having too many superpowers and not enough training or experience to understand them meant that Thouser couldn't use any of his powers effectively. Combined that with losing focus on his already mediocre martial arts skill and he fared worse against Zero-One after stealing all of his abilities than he did when he fought with his inherent power.
- Tradesnarkā¢: All over the place. The transformation announcement even sounds like a commercial jingle, and his Finishing Move cards have ZAIA copyright information.
- Unskilled, but Strong: Thouser's enormously powerful suit and Power Copying weapon make him monstrously strong on paper: the data books put him just a little bit behind MetalCluster Hopper and Rampage Vulcan in terms of raw power. In practice, Gai himself is an unimpressive fighter by Rider standards—he lacks the skills to capitalize on his suit's full capabilities or those of the powers he copied, and shows no signs of improving with experience. Instead he relied on the flashiest, most easily-used power in his collection without any consideration of the creative applications of the bulk of his arsenal. This focus on direct power and lack of growth leads to him falling behind the other Riders who all refined their abilities and improved their technology over time. Just to rub salt in the wound, Thouser was so sloppy that by the latter part of the series, Aruto, Horobi, and even Yua all defeated Gai with nothing but their base forms just by being that much more skilled than him.
- Villain Decay: Thouser is an unstoppable force when he first appears, and for several episodes afterwards...until he's finally beaten. He then gets beaten again in practically every episode he appears in, each more humiliatingly than the last.
- Villain Forgot to Level Grind: Unusually for this trope, Thouser does actually level grind in nearly every episode that he appears in, making use of the Thousand Jacker to steal more and more powers that he can use at the push of a button. Throughout it all, however, he does nothing to address his real problem in a fight, which is his lack of combat skills. This causes his level grinding to be a hindrance rather than a help since he doesn't bother to learn how to use any of his stolen powers effectively and his reliance on them makes him neglect his already mediocre martial arts skills. When facing opponents powerful enough to be a threat, he tosses out his powers haphazardly or forgets about all but the easiest to use entirely. By midseason, the finite number of Riders actually imposes a level cap on the Thousand Jacker's primary function. Meanwhile, every opposing Rider has either gained power roughly on par with his (Vulcan, Jin), can match him based solely on their exceptional skill (Horobi, Valkyrie), or in Zero-One's case, both. Even after Gai ends up needing to completely rebuild the suit, he doesn't bother to make any improvements to it whatsoever.
- Weapon Specialization: He uses his personal Cool Sword, the Thousand Jacker. Eventually subverted as more than one copy of the Thousand Jacker appear in later parts of the series.
- We Named The Dog Indiana: Turns out the name Thouser came from this Robot Dog toy Gai used to have.
- Yin-Yang Bomb: Thouser uses both a Zetsumerise key and a Progrise Key.
