YMMV / Kamen Rider Zero-One

• Alternate Character Interpretation: Aruto and Is's relationship is one that is quite contested by the fans. Is it a romantic one, or a platonic one? There is evidence for both, but it stays on the middle line so well that it's difficult to determine which one it is, as nothing is outright romantic, but the way they interact and help one another is far too close to be simple friends.
• Anti-Climax Boss: Despite being built up over the course of the entire show, Ark-Zero's final battle against Zero-Two and Horobi ends rather abruptly, and it's killed very quickly by Raiden right after.
• Ass Pull:
  • Gai Amatsu revealing that all the puppy soccer he's played throughout the series is because he loves Hiden Intelligence and likened Korenosuke and Aruto's fixation on HumaGears to an incident from his childhood where his father made him give up a beloved robot dog in order to focus on "bigger and better things," considering it all to be a waste of the company's potential and AI technology as a whole comes completely out of left field and is given no buildup at all.
    • His subsequent Heel–Face Turn also has no buildup and comes very abruptly. Prior to #38, Gai Amatsu was shown to be a cold, self-centered sociopath perfectly willing to torture Fuwa just to demonstrate his hold on him. Yet getting a robot dog apparently causes Gai to develop a sense of empathy and decide to embrace Aruto's vision.
  • Aruto becoming Ark-One was not properly set up at all before it happened. Prior to #42, Aruto had been established to have a strong moral core, yet losing Izu is apparently enough to get Aruto to abandon all his previous principles. It's made worse by the fact that he didn't even need an Ark Driver to defeat Horobi, his Zero-Two Driver would have been more than enough, and by the next episode he clearly knows Azu is manipulating him, yet chooses to keep using the Ark Driver anyway. It's rather obvious that it wasn't meant to happen originally, and was the result of last minute changes.
    • Related to the above (and presumably also the result of the aforementioned changes), the Zero-Two Driver crafting a hologram of Soreo Hiden in the penultimate episode to deliver a Rousing Speech to Aruto right after Isamu's "I Know You're in There Somewhere" Fight has the trappings of a Hand Wave rather than something it should conceivably be able to do on its own.
• Awesome Music: Can be found here.
• Badass Decay: Yua Yaiba, hard. While the first few episodes establish her as a tough-as-nails, cool and intelligent Action Girl, it isn't long after that she gets pushed to the background in favor of focus on Aruto and Isamu. She then goes on to become Gai's pawn, commit one of the biggest blunders in the series by setting loose the Ark, and becomes mostly irrelevant to the events that happen after. Even in her own movie, Vulcan and Valkyrie, she's a Faux Action Girl who loses her ability to transform halfway through.
• Base-Breaking Character:
  • Aruto Hiden himself. Is he a fun and quirky character who's engaging to follow, or is he a bland and obnoxious one who has an uninteresting arc for most of the show. Furthermore, his tenure as Ark-One. Was it an unexpected twist that made sense given the events that led up to it and an example of how even all-loving heroes and nice guys can reach their breaking point and snap, or was it just an compilation of contrivances with Aruto using the Ark Driver despite having the Zero-Two Driver, one of the strongest driver of the setting, being fully aware that As isn't Is but still falling for her manipulations and far too contrived, given how Aruto was established to have an strong moral code and Is's death being seemingly enough to make him snap.
  • Fuwa was generally well-liked in the beginning, but he's received some criticism for several of his impulsive moments, particularly in the final arc when he berates a distraught Aruto, tells him not to go fight a genocidal terrorist who would very likely kill people in left unchecked, and then jumps to attacking his former friend even as Aruto is trying to back away from him and in the Zero-One Others films, where he decides Kamen Rider Metsuboujinrai can't be reasoned with based on a vague conversation he had with Horobi, ignores all evidence that the Metsuboujinrai.net members are Fighting from the Inside and goes to kill them all off, resulting in the movie's controversial Downer Ending. Whether these are Idiot Ball moments or not is debated between fans.
  • Horobi has people split between whether he's a cool and stylish villain with an interesting character arc, or a boring one with a wooden and two dimensional personality who changes little throughout the series. Him being the Final Boss also has people split, with some finding it a unique twist while others feel it was undeserved and would have preferred the Ark or a different villain being the final foe instead. There's also those who criticize his actions in the final arc, with him becoming one of the biggest Karma Houdini in the franchise, given how he murdered Is for purely petty reasons yet effectively gets off scot free in the end, gaining back his surrogate son while Aruto lost the original Is, luckily in The Movie, turns out original Is's death didn't stick.
  • Gai Amatsu has proven to be a pretty controversial character. His fans like him for being a devious, formidable, and enjoyable Hate Sink and Manipulative Bastard that's always at least a step ahead of the heroes even when they manage to pull a victory over him, while his detractors find him to be uninteresting and comparatively annoying Smug Snake who only gets away due to Plot Armor and the rest of the cast catching the Idiot Ball, as well as him lacking other traits which make Kamen Rider villains enjoyable. His redemption has also been met with contestation, with many feeling it was undeserved given how he was effectively the cause of the entire show. Though some also argue that lack of buildup aside, the redemption itself is handled fairly well, since Gai's crimes aren't immediately forgotten soon after, and he legitimately pulls his weight when he has to work his way towards truly earning the heroes' trust. Detractors counter by pointing out that Gai's apology for what he did is very vague and non-specific, that he never shows remorse when confronted by other victims of his actions (like S in Kamen Rider Zero-One: REAL×TIME) and that the heroes never actually hold him accountable despite still resenting him and having ample motive to.
• Broken Aesop: The final arc's aesop against revenge and hatred would land better if the previous arcs hadn't encouraged you to hate Gai and take joy in his misery. It also doesn't work on its own, since Horobi's killing of Is was out of a desperate attempt to Hand Wave his burdgeoning emotions and scapegoat humans (despite acknowledging his love for his son Jin being what freed him from the Ark's control in the first place) and would have killed countless people if left unchecked, giving Aruto ample reasons to oppose him. The reason things spiral out of control isn't because Aruto tried to get revenge, but because he used the Obviously Evil Ark Driver, which convinced his friends he'd gone off the deep end despite ample evidence to the contrary and thus spent the latter half of the arc being lectured about his gear instead of properly helped through his trauma; only causing things to reach a boiling point.
• Broken Base:
  • The Workplace Competition Arc is an very polarizing arc. While most agree that the arc was (at least on-paper) an interesting way to introduce Aruto to how cut-throat the business world can be and that it went on for way too long, the divisiveness stems from how far the good outweighs the bad. Detractors see the arc as taking the idea way too far: being an over-bloated spectacle that allowed Gai Amatsu carte-blanche for an majority of the arc, the amount of Idiot Balls tap-dancing past Willing Suspension of Disbelief on so many occasions that Aruto (who spends most of the arc getting effortlessly ragdolled) was hard to root for and especially how formulaic the competition ended up being tend to comes up against the arc. Supporters, however, spin this for the positive: emphasizing the importance of Aruto receiving a wake-up call in addition of getting Metal Cluster Hopper, allows Character Development for Is and the other side characters, giving Fuwa an interesting Mind Control side-arc, Kamen Rider Thouser's well-received fighting style, the token HumaGears of the arc being fine meme-material and the competition serving as an Breather Episode after the previous one that isn't without its serious moments like Metal-Cluster Hopper or Jin's return as Burning Falcon also generally come up in the arc's favor.
  • The final arc involving the rise of Ark-One, the final battle between Aruto and Horobi, both blinded by grief and revenge over the deaths of Izu and Jin respectively and the show commenting on the dangers of revenge as a whole is either a great way to build upon the themes of malice that was present in Zero-One, the proof that the writers could adapt themselves to the pandemic like it's sister show and the heartwarming moments that came out of this with the importance of compassion and forgiveness to fight against hate, or was it an poorly-written plot full of contrivances and a message that contradicts itself with Is and Jin's deaths being contrived, Aruto becoming not only Unintentionally Sympathetic but his transformation into Ark-One being nonsensical and didn't need it to get revenge, his friends being dismissive of his loss and not even bothering to reason with him, the final arc happening entirely by Horobi's fault and him and Gai ending up as Easily Forgiven Karma Houdinis, receiving no punishment for the murders and suffering they both caused and getting away with actions that would have made any other Kamen Rider villain irredeemable.
  • The Zero-One Others V-Cinemas are either interesting films with cool villains that serve as intense, drama-filled swan-songs for fan-favorites while turning the season finale's flip-floppy Cycle of Revenge morals on their head or they're a grimdark mess in the vein of Amazons that destroys a bunch of fan-favorites and un-does everything the protagonists fought for to preach a moral it can't handle any better than the main show does.
• Catharsis Factor:
  • After eleven episodes of featuring HumaGears that turned into Magias are beyond saving, #17 softens this by introducing remotely-hacked Ark Magias. The kicker? The next episode revealed that any victim turned into one and destroyed still had their AI retrievable and saved into a new body.
  • Every time Gai gets beaten up is intended as this, considering how he gets away with his crimes, cheating in the "Workplace Competition" and having a lot of Kick the Dog moments. It starts in #22 with Gai getting soundly trounced by Zero-One's Metal Cluster Hopper. Later, after Gai coldly tortures Isamu with the chip in his brain, he gets beaten down by RampageGatling Vulcan. It further turns out that Gai winning the Workplace Competition and taking over Hiden Intelligence was a Meaningless Villain Victory, leading to yet another beatdown with a clear face of Gai at being outsmarted. In #32, he gets thrashed yet again, this time by Naki and Fuwa teaming up. Then, in #33, Yua turns on Gai and slugs her now former employer in the face. This is followed by Horobi beating Gai after Aruto saves him from a Stinging Scorpion-powered Jacking Break in #35, the four members of MetsubouJinrai.net beating up Thouser in #37 and Gai getting defeated by Aruto once again after Shesta exposes evidence of his unethical conduct in #38.
    • Bizarrely, the show may have inadvertently inverted this. Because of how predictable his beatdowns become and how Gai is effectively demoted from serious villain to comic relief in the third quarter, any satisfaction from seeing Gai get put in his place again gets whittled away the more and more it happens.
  • In #24, with Aruto now in control of Metal Cluster Hopper, not only can Zero-One revert HumaGears back to their original forms without destroying them, he also gives Thouser an even bigger beatdown.
  • Considering Horobi killed Izu for petty reasons an episode before, watching Ark-One beat down Horobi and completely decimate his army of Magia in #43 can be quite satisfying.
  • Given how Unintentionally Unsympathetic he behaves in the final few episodes, Fuwa getting brutally beat down by Aruto in #44 can come off as a lot more enjoyable than was probably intended.
• Complete Monster: Azu is an Evil Knockoff of Izu created by the Ark to usher in its revival who, in contrast to the rest of MetsubouJinrai.net, worships the Ark for the malice it spreads. After the Ark's defeat, Azu manipulates Aruto and Horobi to become new Arks in an attempt to trigger a destructive Robot War. When that plan falls through, Azu empowers Kamen Rider Eden in another attempt to recreate the Ark.
• Contested Sequel: In comparison to Kamen Rider Zi-O. Some praise Zero-One for having more consistent, realistic, and varied characters with great development, and attempting to have one of the more well-realized and interesting settings in Kamen Rider's history. Others however, criticize this show for not innovating upon the Rider formula far more than it could have, having characters act implausibly stupid to further the story, dragging out certain plot points for too long, or poorly handling some characters (Gai’s motivations and his subsequent Heel–Face Turn, Yua’s motivations, Aruto becoming Ark-One). Not helping matters is that Zero-One was unfortunately cut short due to the pandemic, leading to a rushed ending in order to keep on schedule. Quite the Broken Base.
• Creepy Awesome: Aruto as Ark-One is nothing less than completely terrifying and awe-inspiring. Every fight scene featuring this form showcases him as nothing less than an uncanny and foreboding force of nature both in and out of suit.
• Critic-Proof: Zero-One has been lambasted for its messy plot, but its toy sales are still quite a success. In fact, its toy sales are the second most successful in the franchise next to its immediate predecessor, Kamen Rider Zi-O.
• Crosses the Line Twice: Making Isamu laugh when it seems nigh impossible at first is one thing. Making him laugh when he’s still recovering from grievous injuries AND major surgery is very, VERY bad. But still funny.
• Designated Evil: Aruto's crusade for revenge in the final arc. We're clearly meant to see him as Jumping Off the Slippery Slope, yet while he's certainly a lot more unscrupulous, even as Ark-One Aruto only wants to kill Horobi, not fighting the other Riders until they attack him first, and it's hard to fault him for wanting to kill the genocidal terrorist who murdered his beloved robot secretary in cold blood.
  • Part of the reason it comes off like this is that other Kamen Rider shows have featured similar scenarios where the villain kills the hero's female companion and goes on a rampage, and the hero goes to stop them and get revenge, where such a response is portrayed as justified. The only thing that sets Zero-One apart from a show like Wizard in that regard is that Zero-One had Aruto using an "evil" Driver to get his revenge.
• Designated Hero:
  • Gai Amatsu post-Heel–Face Turn. It's hard to ignore that, in spite of his turn, he's still responsible for the Daybreak Town Accident and subsequently the entire plot of the show. It's also hard to root for him when he's going up against villains like S from REAL×TIME (who lost his wife after her insides were painfully torn apart by nanomachines) since he was shaped by events Gai directly caused. Also, even though he's supposedly good, he's never shown actually fretting over his past misdeeds, the most being an incredibly vague apology he gives to Aruto, Fuwa and Yua.
  • Aruto's friends are framed like the rational party of the Ark-One situation - trying repeatedly to talk (and in Fuwa's case "beat") Aruto out of Jumping Off the Slippery Slope and battling Horobi, yet their attempts to get through to Aruto are underscored by Aruto's lack of aggression and the group's immediate mass-De-power; making Aruto the only one capable of stopping Horobi in any capacity.
• Designated Villain: Masamitsu Yuto, ZAIA's candidate for the politician round in #28, is portrayed as a Corrupt Politician for wanting to ban HumaGears and accepting donation money from ZAIA executives. Except Yuto makes valid points for why HumaGears should be banned, that being that they have the potential to steal jobs and are shown in-series to be hacked into harming humans, and ZAIA isn't donating to him to influence his policy positions, but because of his anti-HumaGear position, which he advertises in public and which has widespread support among his constituents. The worst Yuto does is some employ sleazy tactics (having plants in his crowd to make his support seem bigger and lying about his ties to ZAIA) and he's even proven to be correct at the end of the episode when Hiden's HumaGear representative willfully turns violent and makes threats.
• Draco in Leather Pants:
  • As a side effect of his sudden sympathetic backstory and Heel–Face Turn, many fans try to downplay Gai Amatsu's atrocities or even justify his actions by bringing up the actions of MetsubouJinrai and other such villains, even though intentionally led the Ark to hate humans and did countless other things that endangered human lives, making him the Greater-Scope Villain.
  • Horobi also gets an ungodly amount of this from his fans, who like to ignore that Horobi committed some of his worst crimes like murdering Is entirely out of free will, or draw a false equivocation between it and Aruto accidentally killing Jin, even though Jin only died because he deliberately threw himself in front of his Rider Kick to save Horobi, and Horobi was a terrorist actively threatening people at that time, so even if Aruto was doing it out of revenge, he still had ample justification to use lethal force against him.
• Ending Fatigue: The series could have ended at #41 with the (supposed) destruction of the Ark, but Horobi just had to be a dick. Cue four more episodes of extra plot that could have been resolved in one or two had the characters not kept catching the Idiot Ball.
• Ensemble Dark Horse:
  • Fukkinhoukai Taro, the Macho Camp comedian-type HumaGear and the Starter Villain in the first episode, made an impression to Japanese audiences. He even gets fan art in Pixiv. He even returns in a Youtube spinoff.
  • Many viewers took a liking to Seine, due to the Pretty Cure connection (her actress voiced the protagonist in KiraKira★Pretty Cure à la Mode). It is also because her backstory and fate was considered one of the saddest — if not the saddest — in the series.
  • Is's quirky, detective brother Wazu is also beloved for his odd behavior, surprisingly impressive investigative abilities, and his kind-heartedness, despite dying only after two episodes.
  • Smile Sumida also gets trending in Twitter, partially because of her Nice Girl traits. The fact that her actress was also an Idol Singer and gravure idol might have also contributed to this.
  • In #44, an unnamed, cat-ear wearing Maid-type HumaGear protester, and attacking Yua with a placard in which Yua would not respond, is also being the talk of Japanese fans in Twitter, to the point that she got her own fanart.
  • Lyon Arkland from Zero-One Others is well-liked from his Evil Is Cool demeanor, his speech about his motivations as a Corrupt Corporate Executive, and his Gratuitous English, many were upset to see he was only used in one V-Cinema.
• Epileptic Trees:
  • The hooded person in #18, implied by Horobi to also be a member of MetsuboJinrai. There are several guesses as to who they could be, with a few on the internet believing they could be the long-haired Is from the opening, while others claim they are the "Bou" of MetsuboJinrai, judging by its members' names (Horobi/Metsu, Jin, and Rai(den)/Ikazuchi). #25 revealed their name is Naki, which means "death" or "deceased", which also happens to be what "Bou" can be translated as.
    • On the subject of the long-haired Is, after the first part of the President Special aired, some fans believe that the long-haired Is is the Ark either hacking Is' body or simply mimicking its appearance. The fact that long-haired Is sports red-eyes at one point during the special and has the MetsubouJinrai.net marker on the back of her left hand adds further fuel to the fire. Ep 35.5 reveals that the long-haired Is is in fact a member of MetsuboJinrai.net as Ark's messenger, As.
  • Thanks to Horobi taunting him that he might not be as in control of his actions as he thinks, there is also a popular fan theory that the hooded person may be a split personality of Isamu, created from the Ark somehow hijacking his mind when he first used the not-for-humans Assault Wolf Progrise Key and using a female voice to mask his true identity. This is further supported by how aside from those chosen to be Raiders, Isamu is the only other character who has had any form of interaction with them, played such that it looks like hallucinations happening in his mind, while both Horobi and Jin taunted him with the phrase "they might be closer than you think" whenever he questions them about their whereabouts. This was later proven true to an extent as it turns out Gai had an A.I. chip installed in the brains of ShotRiser users to allow them the ability to use it. After he was hospitalized during the climax of the first arc, the chip inside Isaumu became Naki's Soul Jar, which meant that Naki had been inside Isamu ever since.
• Esoteric Happy Ending:
  • A lot of what's set up in the final arc doesn't get a proper resolution within the show. Aruto and Horobi put aside their hatred of one another, yet the underlying factors which led so many HumaGears to follow Horobi and made a Robot War an imminent threat go unaddressed. And As is still out there, handing out superpowered evil drivers, so there's not much of a reason why it couldn't happen again in the future. Gai Amatsu, the one who caused the whole conflict in the first place, also gets off scot free after a very hazy redemption. The revived Is being essentially a copy of the original who lacks her memories can also leave a bitter taste in ones mouth, though thankfully she gets her memories restored in The Movie.
  • The conclusion to Zero-One Others: Vulcan and Valkyrie has Isamu freeing the members of MetsuboJinrai from their containment within Kamen Rider MetsuboJinrai, at the cost of killing the HumaGears and leaving the fate of Isamu ambiguous, with most assuming based on The Stinger that he died. While the V-Cinema ends with the implication of a Bittersweet Ending, it feels very much like Yank the Dog's Chain, especially with its themes on redemption and forgiveness shown with Horobi and Gai in the main series.
• Evil Is Cool:
  • While he was already a fun Psychopathic Manchild before, Jin's return as Burning Falcon sees him becoming a stylish Badass in a Nice Suit and a fairly competent Chessmaster. Of course, by this point Jin's villainy is debatable.
  • Ark-Zero, for the dark, epic aura around it, how it dominates every Rider in fights and is portrayed as an unstoppable force of nature.
  • Lyon Arkland from Zero-One Others leaves quite an impression despite only being the villain of a V-Cinema, on account of being a very stylish and charismatic antagonist with a lot of flair to his personality. There are many who even posit that he's the best villain in Zero-One, especially since he's one of the few not to be Stupid Evil.
• Fan Nickname:
  • "CEO Rider" for Aruto.
  • "Robo-Waifu" and Kawaiizu (かわis) for Izu.
  • "Fuwawa" for Isamu, for being compared to an aggressive chihuahua in his hate against robots.
  • "Gori-rise" for Isamu's brute force opening of Progrise keys.
  • "Dark Cure Whip" or "Another Cure Whip" for Seine, due to having the same actress.
  • Kamen Rider Souther for Thouser, due to similar naming.
  • Prior to being revealed as Naki, the hooded figure passing out RaidRisers during the Workplace Competition arc was referred to as “Bou”, the one kanji in the name “Metsuboujinrai” that hadn't been represented yet^note Horobi, Jin and Raiden are the other three.
  • When the Presidential Specials confirmed that Is and As, her long-haired variant from the OP were separate characters, the latter would be differentiated by the oddly appropriate name of "Isn't".
  • Kamen Rider DARLING in the FRANXX: Aruto's new form is called "Zero-Two", and is the name of the female heroine of the mecha anime. REAL×TIME takes a step further when Is becomes the second Zero-Two.
  • Kamen Rider Unlimited Blade Works for the scene in Episode 44.
• Fandom Rivalry:
  • Like Ex-Aid before, it also gains a friendly rival in the form of Sword Art Online, particularly the Alicization arc, due to the similarities between their respective characters and the concepts of Artificial Intelligence as one of the central motifs of the respective stories.
  • It also has a small case of this with DARLING in the FRANXX, mainly due to their Darker and Edgier nature, the similarities between their respective characters (hero, villain, and Monster of the Week alike), and having major production issues (and that is before the COVID-19 pandemic broke out). While many Zero-One fans believed that the series is "DarliFra done right", there is one thing they unconditionally appreciated and agreed on: the "Zero-Two" jokes.
• Fanon Discontinuity: With the final episode preceding it and the Zero-One 01̶hers duology following it both being seen as Audience Alienating Endings for various reasons, many would prefer to treat the Kamen Rider Zero-One: REAL×TIME movie as the true ending to the Zero-One story and ignore the duology’s Happy Ending Override.
• Franchise Original Sin: A lot of things people complain about with the Zero-One Others films (characters ignoring information they know or options that are available to them, and that resulting in things going From Bad to Worse) are issues that were already present in the show itself. One of the reasons things get as bad as they do in the films is because the villains exploit issues that the characters left unaddressed in the TV series.
• Harsher in Hindsight:
  • Wazu's enthusiastic behavior in hopes of Is calling him "Big Brother" is definitely heartbreaking seeing as how he only got it from her after a Heroic Sacrifice. Made even worse when you realize his sacrifice to power the Shining Hopper Progrise Key would be in vain thanks to the consecutive curbstomp battles from Gai that rendered both it and the Assault Trigger obsolete.
  • Is avoided death that far back. She does eventually die towards the show's end. Compared to her brother, which had a positive consequence, this has a far more negative consequence.
  • Jin delightfully asking Fuwa if he's joining MetsubouJinrai.net becomes a lot more darker given that the ending of Vulcan's movie has him going into the afterlife alongside the members of MetsubouJinrai.net.
  • A more tearjerker example is how Aruto incorporating the voice of Seine, a deceased person, into an Alexa-like device for her father ended up predicting how Amazon plans on doing the same for Alexa.
  • Gai's vendetta against AI and preaching about how HumaGears will replace humans in the workforce, as well as Choichiro using HumaGears artists to do the job for him, while not an unfound fear in past works, ends up being eerily similar to concerns over AI generated art, made even more eerie given the controversy surrounding them began over a competition, something that was a part of Gai's plan to take over and destroy the HumaGears.
  • Related to this is how one of the competitions involve two lawyers, one being a human and the other a HumaGear, the latter that is becoming all the likelier with the advent of ChatGPT. Then there's how it ends with a politician accusing his HumaGear opponent of creating a fake video to make him look bad, something that is becoming increasingly common with deepfakes having more advanced AI-driven text-to-speech capabilities.
  • The Ark-One episodes and the aftermath of the Zero-One Others movies would become this come Kamen Rider Outsiders. Aruto is among the heroic Riders who supported Zein's malice-free ideology and Gai having to form a reluctant alliance with the Ark to stop it, essentially finding themselves in an Hourglass Plot of their feud during the Workplace Competition arc and given the circumstances after the events of Vulcan & Valkyrie, both of their efforts to bury the hatchet becomes All for Nothing. Doubly so once Zein would turn out to be no different than the Ark and had concluded to destroy humanity through Kamen Rider Chronicle.
  • Related to Outsiders and crossing with History Repeats, the fact that the good guys programmed Kamen Rider Chronicle into the Zein Driver would allow Zein to use the Deadly Game to send humanity down to the path self-destruction. Congratulations, you just repeated Gai Amatsu's corruption of the Ark and doomed the entire world!
• Hilarious in Hindsight:
  • Earlier in June 2019, a series of toy catalog scans for Zero-One was revealed, claiming the series would take on a “company/business” theme, with forms and powers based on business suits and job classes. While eventually proven to be fake, multiple elements of the theme were actually used in the story:
    • The main character Aruto Hiden, who unexpectedly becomes president of a major company, and was named as the “Company President Rider” in the official trailer.
    • The multiple uses of the Arc Words I am the President and a Kamen Rider counts towards this as well.
    • The initial weapons for the Riders are all converted from briefcases.
    • The second and third arcs have the story turn into a Corporate Warfare in the guise of a Tournament Arc between Hiden Intelligence/Manufacturing and ZAIA Enterprise.
    • The catalog names the secondary Rider as Kamen Rider Zero-Two. The Zero-Two name eventually does get used, but as Zero-One's Super Mode instead.
  • In the earlier releases of the DX Ziku-Driver, there was a Manual Misprint in which the instructions indicated that one of the singers of Over “Quartzer” was Takanori Nishikawa, instead of ISSA. Bandai Namco later released a statement confirming this error, and was to fix it in future productions of the DX toy. Guess who became one of the singers for the opening theme song for Zero-One, REAL×EYEZ?
  • When the toy line was first revealed, many complained that the Progrise Keys didn’t have a button to open the keys (before the show revealed that they needed to be scanned before opening). Come #17, and it turns out that Thouser’s Amazing Caucasus key opens exactly like this.
  • Our hero loses his longtime robotic partner, and in his grief he builds a replacement that has none of her original memories - until the followup to the series has said robot regain all her memories after coming into contact with what the original had left behind. Are we talking about Zero-One or WandaVision?
• Inferred Holocaust: Remember in #9 when Aruto shutting down all the hospital care HumaGears caused a lot of disarray? You'd expect Gai shutting down every single HumaGear at the end of the Workplace Competition arc to cause even more chaos, but whatever greater effects it would have had on society aren't depicted, and by the final arc things seem to have returned to normal offscreen.
• Informed Wrongness:
  • Even if he's technically responsible for the whole crisis, Gai isn't wrong in pointing out that HumaGears are dangerous since we several times that all it takes for a HumaGear to go crazy and become a Magia is for a human to insult or belittle them. He's also not necessarily wrong when he markets his ZAIASpec as superior to HumaGears, especially considering it enhances a person's ability to perform a specific task rather than supplant them like a HumaGear does.
  • Despite the newfound vengeful tint to his crusade against Horobi, Aruto is not wrong to oppose him in the last arc. Horobi's threats to implement a Final Solution against humanity are very much real and with his friends depowered, Aruto's the only one that can stop Horobi anyway, Ark Driver or no.
• It Was His Sled: From REAL×TIME: Is becomes Kamen Rider Zero-Two and fights alongside Aruto!
• Memetic Loser:
  • Because of how he is always on the receiving end of a Curb-Stomp Battle since Aruto learned how to control Metal Cluster Hopper, how he gives upgrades to Aruto and Isamu without realizing the consequences of his actions before it's too late, and having perhaps the biggest Meaningless Villain Victory in the history of Kamen Rider, a lot of fans like to joke about how pathetic Gai Amatsu is.
  • Yua Yaiba is effectively the Kamen Rider franchise's new go-to example for Faux Action Girls. Despite being marketed as the first female tertiary Rider and a highly competent fighter, her role diminishes as the series goes on and whenever she fights an opponent tougher than a mook she usually loses if she doesn't have help. There's also the fact that her only significant contribution to the overall plot was accidentally reviving the Ark. Thus it's become common for fans to make jokes about how useless she is in the series. Vulcan and Valkyrie does little to mitigate her status as this, as her new form in the movie is retooled from one of her other forms, and she loses her only fight with it, spending the entire second half of the movie unable to become a Rider. Not helped by the fact that the next three Reiwa seasons all featured highly skilled and developed female Riders, or by the Girls Remix special, in which Valkyrie's appearance amounts to a short cameo where she gets thrown on her rear end by the villain of the special.
• Memetic Mutation: See this page for examples.
• Mis-blamed: Not a person but an event. The 2020 pandemic is commonly cited as the reason Gai Amatsu's redemption in #38 was so rushed, yet according to one interview, the writers had already written up to #39, with the plot points after being the things that were rewritten.
• Moe:
  • Is for many fans. Her surprisingly dorky moment of misinterpreting an innocent statement for one of Aruto's jokes and explaining it before delivering his Catchphrase as a comedian in #3 only bolstered the number of people who find her cute. It came to the point that in Pixiv, Is currently has the highest count of fanart for a Rider female protagonist, surpassing Poppy from Ex-Aid.
  • Jin for some other fans. For a Psychopathic Manchild who works as The Brute for the Big Bad, he talks and acts like a five-year-old boy.
  • The new version of Thouser (the dog, not the Rider), especially as it dances to the Metal Cluster Hopper jingle. Even better, the prop used is one of Sony's real-life Aibo robotic puppies, and for a limited time, they were able to do the exact same dance as the one in the show when the toy version of Metal Cluster Hopper is activated in its presence.
• Moral Event Horizon: See this page for examples.
• More Popular Replacement: Lyon Arkland was created to be a Replacement Flat Character for Gai Amatsu in the Zero-One Others films, but many consider him to be a superior villain to Gai because he's legitimately cunning and intelligent, has actual beliefs instead of being a greedy hypocrite, and is overall a lot more flashy and fun of a character.
• Most Wonderful Sound: As per usual, the Zero-One Driver and the Progrise Keys.
  • Jump!
  • Authorise! Prog-Rise! To~biaga-Rise! Rising Hopper!
  • The OP theme, REAL×EYEZ by J and Takanori Nishikawa: Zero-One, Zero-One, Zero-One, Zero-One...
  • A.I.M.S. Shot Riser’s standby is very catchy as well: a very robotic "Kamen. Rider." repeated over and over.
  • There is also the sound along with the visual of each letter stamped one by one on the screen as the finisher is about to be announced. The finisher voice itself also qualifies.
  • Metal Cluster Hopper's sounds, Everybody JUMP!, "Let's Rise! Le-le-let's Rise!"
  • Rampage Gatling's Henshin sound as well, All-Rise!
  • Zero Two - Zero Two Jump!, Zero-Two Rise, Road to Glory has to lead to growing path to change! One to Two! Kamen Rider Zero Two, It's never OVER!.
  • The sounds for Abaddon's weapons are a mix of Electronic Dance Music and rock that will make it easy to forget they belong to Mooks.
• Narm:
  • The sheer amount of times Gai gets beaten up and/or humiliated in the Hiden Manufacturing arc. It starts off fun but it just gets ridiculous over time as his defeats get dragged out more and more, and mitigates the catharsis that could be gained from it.
  • Gai's Freudian Excuse being that his dad told him to study more and play with his robot dog less. It's sad on its own, but it's rather jarring to see that Gai went from a boy sad about his robot dog to a psychopath who mind controls and tortures people for fun.
  • Horobi's constant proclamations in the final arc that he has no heart come off more as an Emo Teen trying to be "edgy" and make him hard to take seriously.
• Narm Charm: The last bit of the Progrise Keys calls. Even with the Gratuitous English and the monotone text-to-speech voice used (save for Thouser's, which sounds like a dramatic TV announcer), it manages to come off as sounding super cool after a Transformation Sequence:
  Rising Hopper: A jump to the sky turns to a Riderkick.
  Flying Falcon: Spread your wings and prepare for a force.
  Shooting Wolf: The elevation increases as the bullet is fired.
  Rushing Cheetah: Try to outrun this demon to get left in the dust.
  Biting Shark: Fangs that can chomp through concrete.
  Punching Kong: Enough power to annihilate a mountain.
  Flaming Tiger: Explosive power of 100 bombs.
  Lightning Hornet: Piercing needle with incredible force.
  Freezing Bear: Fierce breath as cold as arctic winds.
  Breaking Mammoth: Larger than life to crush like a machine.
  Shining Hopper: The rider kick increases the power by adding to brightness!
  Shining Assault Hopper: No chance of surviving this shot.
  Assault Wolf: No chance of surviving.
  Burning Falcon: The strongest wings bearing the fire of hell.
  Rocking Hopper: Kamen Rider will fight to protect humanity. Type-1.
  Amazing Caucasus: When the five horns cross, the golden soldier Thouser is born. Presented by ZAIA.
• Replacement Scrappy: Many fans were disappointed to see the Ark reduced to a Disc-One Final Boss and with the final villain instead being As, who is seen by many fans as a Flat Character with uninteresting motives and a convoluted Evil Plan that relied on several characters acting implausibly dumb.
• Robo Ship: It is not hard to ship Aruto and Is together due to their chemistry and how cute they are together.
• Seasonal Rot: Despite being the first Rider Series of the Reiwa era, Zero-One looks to be one to both series headwriter Yuya Takahashi and producer Takahito Omori. While their previous work Kamen Rider Ex-Aid was praised for its well-written storyline, Zero-One was a major nosedive due to some characters' wasted potential, numerous Ass Pulls, the resident Hate Sink being a controversial figure, a poorly executed Broken Aesop, and eventually, the Downer Ending for the post-series content. Some, but not all of that, is due to the rise of the COVID-19 pandemic which causes a lot of changes from it's original plan in the show.
• Shocking Moments: #42 starts with the implication that Horobi is going to become Ark-One. This was actually a simulation that As used to set up Is' murder by Horobi. Her death pushed Aruto over the Despair Event Horizon and allowed As to manipulate him into becoming Ark-One himself.
• Special Effects Failure:
  • The scene of Zero-One leaping through cars in the first episode to get to the Berotha Magia involves some very poor computer graphics, and it's obvious when Zero-One shifts from being a person in a suit to a CGI model.
  • During the motorcycle duel in the second episode, a quick close-up briefly reveals that the bikes are strapped to a moving platform and aren't actually moving.◊
  • #18 has Aruto transform into Zero-One Shining Assault Hopper, but the transformation announcement played was for Shining Hopper instead.
  • In #20, if you focus on Smile during the transformation, you can actually see the moment the footage cuts from Aruto-as-Fumiya-Takahashi to Aruto-as-Yuya-Nawata (the guy in the Zero-One suit).
  • In #40, there's a possible one. The camera is pulled back during one part of the fight where the intent seems to be to highlight Zero Two's speed. During scenes, the original actor leaves the scene just as a second actor comes into frame. This might be a production error, or it might given the structure of the rest of the scene be an intended effect. It's hard to say.
• Spiritual Licensee: Unintentional example with Ryutaro Okada (Isamu/Vulcan) and his own Youtube channel, which has not only been carrying more and more Zero-One related material but even boasts appearances by his co-stars, and has become this season's stand-in for the Zi-O Supplementary Episodes.
• They Wasted a Perfectly Good Character:
  • For someone who has such an important and lasting impact on the setting, the audience knows shockingly little about Korenosuke Hiden AKA the literal creator of the HumaGears AKA Aruto's biological grandfather whom he inherits Hiden Intelligence from. We never do know just how Aruto personally felt about or viewed Korenosuke as a person - something more egregious given that it is heavily implied he did not go to his own grandfather's funeral in #1. We also never know just how much Korenosuke knew about MetsubouJinrai.net, the Ark, and Gai to warn his grandson and company about their threat in his will and be Crazy-Prepared enough to set up so many countermeasures after his death, including exact wording in his will.
  • Yaiba is practically a Faux Action Girl-type throwaway character, given that her motivations for just about anything go unrevealed throughout the series and her characterisation changes between having a Lack of Empathy and having Fuwa as her Morality Pet on a whim. Not to mention that she didn't get any upgrades in her rider form aside on her only form change despite being billed as the series' third rider in the series proper, even gaining some upgrades in the V-Cinema only gives her a short screentime before losing her powers for good.
  • Despite a large build up, the Ark is little more than a Generic Doomsday Villain upon awakening, with no real characterisation or interesting traits to speak of. Before it's plan to eradicate humanity is even known, it's anti-climactically defeated. Some fans have expressed a preference for the Well-Intentioned Extremist Ark seen in Kamen Rider: Reiwa the First Generation and wish that had been the Ark's characterization in the show, instead of a generic villain that wants to kill everything for no reason.
  • Naki and Ikazuchi, the other two members of Metsuboujinrai get very little to do after their revivals beyond resurrecting the Ark, with most of the focus instead being on Horobi and Jin.
  • Lyon Arkland from Zero-One Others. He's a stylish and legitimately intelligent mastermind who gives us some insight into the inner workings of ZAIA Enterprise, but he only appears in one movie. There are a lot of fans who would love to see more of him and wish he got to be the villain of both V-Cinemas.
• They Wasted a Perfectly Good Plot: Likely as a result of being produced during the COVID-19 pandemic, these can happen.
  • Though the HumaGears are central to this season, the topic of HumaGear rights is never fully explored, instead taking a backseat to other plotlines. While it's brought up on occasion, we never get any answers as to what level of rights HumaGears should be given, or what coexistence between humans and HumaGears might even look like, and the season ends with the topic unresolved.
  • After it's revealed Fuwa had Fake Memories implanted into him, we learn his family is still alive. This could have led to an entire about Fuwa reconnecting with his long-lost family, but while they're introduced in #36 we never get to see Fuwa interact with them, and they're forgotten about right after.
  • The final arc never thinks to apply its Cycle of Revenge moral to Gai. Given how almost all the members of the cast had a great deal more resentment for him, seeing characters like Fuwa also try to grapple with their leftover resentment towards him would have made for an interesting plot point.
  • Speaking of the final arc, Aruto's trauma over Izu's death is only barely addressed beyond being Ark-One's catalyst. The rest of the cast is too tunnel-visioned on Aruto wearing the Ark Driver-One to even bother acknowledging it as the reason he's turned so vindictive. What could've been Aruto's friends getting through to the person that's done so much for them and pull him away from the brink to fight without malice is instead reduced to a series of vague skirmishes and tone-deaf proselytizing that his Driver has to become sentient for to conclude.
  • Because Ark-One was changed to an extra final form for Aruto rather than an upgrade to Ark-Zero at the last moment, it never has a proper fight against Zero-Two or any other more evenly-matched opponents. Instead, all of its fights are either it effortlessly curb-stomping opponents far weaker than it or Aruto willingly allowed the Ark-Driver to be destroyed.
  • Gai Amatsu's Heel–Face Turn could have made for a deep and meaningful moment if it had been built up more, and if he'd had his redeeming qualities set up beforehand instead of being haphazardly squeezed into the very same episode he turns good in. Another idea, as mentioned under They Wasted a Perfectly Good Character, was if someone like Lyon Arkland had manipulated even him.
• Too Bleak, Stopped Caring: The climax of the final arc can be hard to be invested in given just how irrational and needlessly malicious everyone acts in it. Is dies for reasons that were contrived and easily avoidable, Aruto becomes Ark-One even though he's aware of the consquences and didn't need the Ark Driver to get revenge, his friends spend more time berating and talking down to him than actually trying to reason with him, and Gai Amatsu and Horobi both get Easily Forgiven and receive no punishment for the murders and suffering they both caused.
• Unexpected Character:
  • No one expected Aruto’s robot dad to play any sort of role after the first episode, least of all a villain in Reiwa: The First Generation. Even his actor expected the role to be a One-Scene Wonder.
  • While the V-Cinemas and specials for the Riders aside from Zero-One were expected, the appearance of Kamen Rider Ex-Aid characters (Kuroto Dan/Kamen Rider Genm and Masamune Dan/Kamen Rider Cronus) as well as the Bugster Virus being an important plot point in Thouser's special was a surprise no one saw coming. The usage of Mighty Action X proto-Gashat is also quite surprising, as it was last seen in Kamen Rider Ex-Aid in #11.
• Unintentionally Unsympathetic:
  • Gai's backstory is that he had an emotionally distant Education Papa who scolded him for playing with his robot dog instead of studying. While it's easy to sympathize with it in isolation, given how Gai did things that were far, far, far worse it's hard to take it as a legitimate excuse.
  • Horobi is supposed be seen as tragic in the final arc, but he murdered Is entirely of his own free will, even though he claimed to be liberating HumaGears, and tried to lead a genocidal uprising against humanity. It's hard to sympathize with him because of this.
  • Fuwa in the final arc. He stops Yua from comforting a grieving Aruto, which is what allows him to be approached by As. And when he finally gets a chance to speak with Aruto again in the final episode, never expresses any empathy for his loss and jumps to attacking him as Ortheros Vulcan without trying to reason with him for very long. You would think given how Aruto was his longtime friend, he would make a better effort to try and explain why killing Horobi was a bad idea, yet he never tries to tell Aruto about the HumaGear protests that are going on and only gives a vague statement about how it would start a war.
• Visual Effects of Awesome: The official website tells what happens behind the scenes for each episode, including the special effects they brought up in certain scenes. Some scenes are portrayed with conventional special effects that are plausible, cost-efficient, and awesome.
  • #5 had Flaming Tiger debuted in flames (reminiscent of Kuuga’s Mighty Form). The catch? No fire or CGI effect was involved. The "fire" was actually vapor illuminated in orange light. Practical and safe, not to mention awesome!
  • #7 has Ansatsu-chan frozen over. The effect is presented with powdered sugar sprayed on the actor.
• Woolseyism:
  • Aruto’s jokes revolve around Japanese wordplay and puns that do not translate well into English, much to the chagrin of many a subbing group.
    • One such group, Rider Time FanSubs, actually went through seven different translations for Aruto’s shine/shain pun in #2.
  • A non-joke example is Over-Time’s translation of MetsubouJinrai.net, which is changed to “ExtinctionThunderstrike.net”. They seem to have dropped that particular translation by #3, however.
  • The subbing group, Genm Corp, lamented on Twitter over having to consult a rhyme generator website to translate the rapper HumaGear MC Check It Out's Rhymes on a Dime way of speech, in order to make them translate well in English.

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