Sandbox / Kamen Rider Den O Kamen Rider Zeronos

Main Character Index | Protagonists (Yuto Sakurai and Deneb) | Imagin | Movie-Exclusive Characters

This is a partial character sheet for Kamen Rider Den-O. Visit here for the main character index. Subjective trope and audience reactions should go on the YMMV page.

Warning: This page contains un-marked spoilers for Kamen Rider Den-O and Kamen Rider Outsiders. New viewers beware.

Yuto Sakurai/Kamen Rider Zeronos/Kamen Rider Zein

Portrayed by: Yuichi Nakamura (live), Makoto Ito (suit; Den-O), Masashi Takada (suit; Zi-O), Kenya Saitou (suit; Outsiders)

This page details tropes for Yuto Sakurai and Deneb. Because of the time-traveling nature of Kamen Rider Den-O, three versions of Yuto Sakurai exist as independent and distinct characters. Here, as in most media, they will be distinguished by their names, "Yuto" referring to the younger version, "Sakurai" to the older, and "Yu" to the youngest version.

Tropes applying to Yuto

Yuto

Portrayed by: Yuichi Nakamura (live), Makoto Ito (suit, Zeronos), Unknown (suit, Zein)
Young Yuto Portrayed by: Ruka Sawaki

"Let me say this to start: I am fairly strong!"

The teenaged version of Yuto Sakurai, as well as the warrior Kamen Rider Zeronos and the partner of the Imagin Deneb. Yuto initially appears after Ryotaro gets too close to Sakurai, warning the soft-hearted young man not to interfere, believing that protecting the timestream is different from protecting individuals, unlike Ryotaro. The brash, hot-tempered Yuto stands greatly at odds with Ryotaro's memories of a gentle, kindly, brotherly Yuto Sakurai, but according to the Owner, the two are indeed one and the same. He also acts childish at times, preferring his coffee overloaded with sugar, despising shiitake, and enacting comedic violence upon Deneb whenever the Imagin annoys him. Contact with Ryotaro and the DenLiner crew tempers Yuto's harsh personality as well as maturing him. The exact nature of his Zeronos powers are explained in tragic detail later in the story.

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• Aw, Look! They Really Do Love Each Other: For all the crap Yuto gives to Deneb, he genuinely cares about him, as in the finale, he was devastated when Deneb disappeared, and upon seeing Deneb alive again, Yuto was about to seemingly attack him again, only to fall into tears in Deneb's arms.
• Badass Normal: He's not a Singularity Point like Ryotaro, but is able to fight as himself using Altair Form long before Ryotaro manages to do the same thing with Liner Form.
• Boke and Tsukkomi Routine: The Tsukkomi to Deneb's Boke.
• Catchphrase: "Let me say this to start: I'm pr-e-tty strong!" ^Japanese"Saisho ni itte oku! Ore wa ka~na~ri tsuyoi!". On a couple of occasions, Yuto replaces the second part with "I'm pretty ticked off!"
• Catchphrase Spouting Duo: Oftentimes, with Deneb.
• Character Tics: Giving Someone the Pointer Finger ("Let me say this to start! I'm pr-e-tty...") followed by the Bicep-Polishing Gesture ("...Strong!").
• Defrosting Ice Queen: A male example. Yuto started the series as a cold jerk and was occasionally quite rude to Ryotaro. He gradually warmed up to him, and by the end of the series, they had become true friends.
• Deus Exit Machina: Hospitalized, and therefore absent, for a good portion of Final Countdown after Taking the Bullet for Kohana, but reappears just in time for the climax. In Onigashima Battleship, the alteration of the timeline causes him to be erased from reality, again.
• Did Not Get the Girl: At least not yet anyway. Much of the Episode Red movie dealt with the fact that Airi can't love the current Yuto the same way she did Sakurai (although the existence of Hana in a younger form implies that the two will eventually get together; presumably once Yuto matures into someone more like Sakurai).
• Does Not Like Spam: He dislikes Shiitake Mushrooms a lot. He gets over it at the end of the series.
• Drunk with Power: In Kamen Rider Zi-O, Yuto is determined to defeat Sougo because he witnessed Sougo as Grand Zi-O in the near future and saw it as a sign of Sougo beginning to transition into Ohma Zi-O from corruption of the unrivaled power he now holds.
• Foil: He acts as a foil to both Geiz and Tsukuyomi in Kamen Rider Zi-O's Den-O arc by his actions and reasoning. He also traveled to the past to kill Sougo to stop him from gaining unrivalled power and becoming the greatest and worst demon lord but will work with Sougo for the greater good like early series Geiz, believing Grand Zi-O's powers is too much for a single person to handle and Sougo will be corrupted by them just like why mid series Tsukuyomi turned on Sougo.
• Heroic Willpower: While Ryotaro can't manifest any decent Den-O forms by himself (until Liner Form), Yuto's stronger will allows him to assume Zeronos Altair Form without the aid of an Imagin.
• Hidden Heart of Gold: Comes with the revelation about the Zeronos Cards, explaining that Yuto acts rude to keep people distant.
• Holding Back the Phlebotinum: With good reason. And, apparently, Sakurai himself has a good reason for giving power with such a drawback in the first place. Erasing his (Sakurai's) own existence allows Yuto to write his own history (in another timeline, anyway).
• Identical Stranger: Sougo mistakes him for Kyosuke Kiriyainvoked during his first appearance, to which he replies that he does not know of such a person.
• In the Style of: Action-Zero = Rock. 2010 Version = Soft Piano.
• Jerkass Has a Point: Yuto's declaration that he's going to kill Sougo to stop the Bad Future in Kamen Rider Zi-O is very harsh but at the same time, it is a fact Sougo is still destined to be Ohma Zi-O, his time powers are incredibly powerful and even Geiz and Tsukuyomi took half of the series to fully trust Sougo.
• Jerk with a Heart of Gold: Yes, he does distance himself from people in a rude way, but he does have legit reasons for doing so, given that he is doing everything to protect his niece Hana.
• Ma'am Shock: Delivers one to Mach during the events of Super Hero Taisen GP.
  "Don't call me Old Man!"
• I'm Not Here to Make Friends: Non-reality show example; he says this outright when Deneb suggests he work with the DenLiner crew.
• Picky Eater: He dislikes shitake mushrooms. The fact that he's eating them at the finale, after believing that Deneb vanished after the Big Bad's defeat shows just how much Deneb means to him.
• Sensitive Guy and Manly Man: Manly Man to Ryotaro's Sensitive Guy.
• Significant Reference Date: When Yuto first makes his debut in the series, he's holding a ticket for May 27th, 2007. Go on, guess the airdate of that episode.
• Sweet Tooth: Yuto really likes his coffee sweet, to the point where he puts way too much sugar in.
• Tsundere: In Kamen Rider Zi-O, he becomes a platonic version for Sougo. After hearing from Deneb Sougo successfully talking down past Takuya, he accepts Sougo and even tells Momotaros to give him the Den-O Ridewatch but denies trusting him.
• Walking Spoiler: The truth behind the source of his powers are meant to be a late-series surprise.
• Well-Intentioned Extremist: In Kamen Rider Zi-O, he spends most of episode 39 trying to kill Sougo because he believes Sougo is destined to be corrupted by his power and create a horrible future.
• Wrestler in All of Us: His way of dealing with Deneb's antics.

Tropes applying to Sakurai

Sakurai

Portrayed by: Tomonobu Okano

Airi's fiance and Ryotaro's future brother-in-law, Sakurai, sometimes known as the Past Man, was a gentle, kind-hearted man with a passion for astronomy he shared with Airi. The two were very much in love, and Sakurai treated Ryotaro like the little brother he never had; thus, Ryotaro's surprise when Sakurai disappeared just before the wedding is understandable, as is his confusion at the fact that nobody seems to remember his existence. Several times in the early part of the series, a cloaked man appears watching Den-O's battles in the past and checking a pocketwatch; by accident, Ryotaro bumps into the man and recognizes him as Sakurai. He attempts to track down the man, only to be warned off by Yuto.

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• Badass Longcoat: Does not show his face, but he fights well.
• Big Brother Mentor: Ryotaro implies he was one, as one of his first conversations with Yuto is to explain the values that he taught him (namely, that even if he has awful luck and isn't very strong, it's not an excuse to do nothing.)
• Big Damn Heroes: When Den-O and Zeronos were having trouble with The Dragon, Sakurai himself steps up to help them in battle, assuming Altair Form.
• Chekhov's Gunman: He shows up, face concealed, at the scene of Imagin battles long before Ryotaro encounters and puts a name to him. He's also hinted at via Ryotaro telling Airi that she "shouldn't forget" in an early episode regarding a woman who wanted to forget her former love.
• Guile Hero: Orchestrates a complex plan in order to protect his future daughter.
• The Plan: Most of the show's plot is predicated on a plan by Sakurai and Airi to protect their daughter Hana from the Imagin.
• Star-Crossed Lovers: With Airi, as referenced by Zeronos' theme (see Yuto's theme).
• What the Hell, Hero?: Deneb tells off Sakurai for making Yuto use the Zeronos cards, even culminating in Deneb throwing Sakurai out of the ZeroLiner.

Tropes applying to Yu

Yu

Portrayed by: Ruka Sawaki

A young boy from Tokyo; after his mother's death he was forced to relocate to his grandmother's in the countryside. He prefers the busier city life instead of the dirtier country life, especially as he hates bugs. Because of his apparent contempt for the countryside, he's nicknamed "Tokyo Boy" and bullied by fellow classmates. His life starts to change after he discovers the Kirifuda, a trump card against humanity that is desperately wanted by the Oni searching his village for it.

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• City Mouse: He was moved to the countryside from Tokyo due to family circumstances, and misses the city life.
• Cross-Cast Role: The actor potraying Yu, Ruka Sawaki is a girl.
• Intergenerational Friendship: He becomes close friends with Deneb in particular over the course of the movie, foreshadowing that he has that relationship with him in the present as Yuto Sakurai. He also befriends Toki, who may be his ancestor.
• It Was with You All Along: The Kirifuda that the DenLiner crew and the Oni had been looking for. He uses it to bargain with the Owner in order to ride DenLiner.
• Parental Abandonment: His mother died long before the events of the movie and his father is in a foreign country, leaving him in his grandmother's care.
• Precocious Crush: Instantly smitten with Toki, the girl that leads the fight against the Oni Brothers, at first sight. Though it might be less of this and more that she reminded him of his deceased mother. The Other Wiki mentions that she is Yu's mother's ancestor.
• Raised by Grandparents: Lives with his grandmother, as his mother is dead and his father is busy overseas.
• The Stinger: As the credits roll, Yu shouts his full name at the bullies from earlier, revealing it as Yuto Sakurai. Furthermore, Deneb tentatively tries to ask Yuto if he remembered him from his childhood. Yuto responds by a Meaningful Echo of Yu's words from earlier.

Tropes applying to Deneb

Deneb/Kamen Rider Zeronos (and New Den-O) Vega Form

Portrayed by: Hōchū Ōtsuka (voice), Yoshifumi Oshikawa (suit)

"Let me say this to start..."

Yuto Sakurai's Imagin partner, inspired by the legend of Benkei and allowing Yuto to transform Zeronos into Vega Form. Deneb is kind-hearted but somewhat on the thick side, his polite friendliness contrasting greatly with Yuto's loud, rude attitude. He often tries to better Yuto, encouraging him to be nicer or to work alongside Ryotaro as an ally rather than viewing the DenLiner team as a hindrance. Occasionally Deneb will even possess Yuto and run around being friendly, doing good deeds, and passing out Deneb Candy in order to win friends for the young man, but this invariably results in a beating from Yuto once he regains control. Deneb's history with Yuto and with the Sakurai that Ryotaro is familiar with is revealed later in the series.

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• Apologises a Lot: One of the humblest Imagins in existence.
• Arm Cannon: Type 1; his hands can fire bullets from the fingers.
• Battle Butler: Acts as Yuto's loyal servant (running errands, cooking, cleaning the ZeroLiner) and partner in battle, complete with being humble and honest to a fault.
• Benevolent Genie: In stark contrast to the other Imagin, Deneb outright defected from the Imagin cause and joined Sakurai under his own free will. Even the Taros required a bit of persuasion before they joined Ryotaro's side. What wish he granted Sakurai was never revealed, although by Onigashima Battleship he was able to possess Kotaro, so we can assume it was completed at some point.
• Beware the Silly Ones: Despite being Yuto's ditzy comedic foil and the nicest guy in the series, his few fights as Zeronos and New Den-O Vega Form show he's actually much better at fighting than Yuto (who's not bad himself).
• Boke and Tsukkomi Routine: The Boke to Yuto's Tsukkomi.
• Catchphrase: Usually begins with Yuto's "Let me say this to start!" ^Japanese"Saisho ni itte oku!", only to mess it up with an honest fact that bewilders everyone around him; he uses "The face on my chest is just for show" ^Japanese"Mune no kao ga kazari da!" a couple of times. He also says "Take care of Yuto!"^Japanese"Yuto o yoroshiku!" both in conjunction with the first phrase and on its own.
• Catchphrase Spouting Duo: Sometimes gives the tail-ends of Yuto's phrases.
• Chunky Updraft: When transforming into Vega Form.
• Demonic Possession: Although as an Imagin he's capable of it, it's rather notable in that Deneb refrains from possessing others outside of Yuto, even when it's established he can. Even when possessing Kotaro, he promptly apologizes.
• Empathic Weapon: Transforms into the Denebick Buster whenever Zeronos assumes Zero Form, and can still talk to Yuto.
• Finger Firearms: All of his fingers are like this.
• Finishing Move: New DenGasher Naginata Mode: Brandish Dive: New Den-O Vega runs through his opponent with the DenGasher with a Rider Thrust.
• The Heart: Has many attempts to appeal, sometimes fail hilariously.
• In the Style of: Action-Zero = Rock. 2010 Version = Soft Piano.
• Malicious Misnaming: Momotaros (and sometimes the other Imagins as well) likes to call him Odebu (a deformation on his name, which literally means "tubby").
• Nice Guy: Deneb is unfailingly polite to everyone, even his enemies, and every time he's in master's body it's for the purpose of trying to make friends with everyone Sakurai pushes away. This stands out particularly in contrast with the more amoral and even malicious Imagin throughout the show.
• Nice Job Breaking It, Hero: Because he didn't tell Yuto of his plans of going through a Haunted House event, Yuto thought that Deneb was in danger when the latter was scared out of his wits; thus, Yuto had to use up a Zeronos card even before finding out what really happened. Yuto didn't like Deneb's actions one bit.
• Paper-Thin Disguise: In episode 40 of Kamen Rider Zi-O, he dresses as a doctor with a lab coat, fake glasses and fake beard but as an Imagin. The disguise does nothing to blend him in.
• Power Makes Your Hair Grow: When possessing Yuto, present or past.
• Shipper on Deck: Ships Yuto with Airi. This gets the limelight in Episode Red of Cho Den-O Trilogy.
• Shoo Out the Clowns: The moment where he becomes conspicuously absent in Kamen Rider Outsiders is when an version of Yuto decides to become the user of the Zein Driver and become Kamen Rider Zein, a Knight Templar who is dedicated to eradicating evil in the most brutal way possible.
• Sixth Ranger: With Yuto, while both of them aren't part of the DenLiner crew, they do team up with them multiple times and are considered the Secondary Rider of the season.
• Spotlight-Stealing Squad: In Onigashima Battleship. Lampshaded in the Kamen Rider Decade net spinoff episode which advertised the movie.
• Trademark Favorite Food: Likes to put shiitake mushrooms in the food he makes.
• What Happened to the Mouse?: He's nowhere to be seen during Kamen Rider Outsiders, which is strange given that it's mentioned that every heroic rider gave their power to Zein, and even stranger considering that the Yuto in Outsiders is revealed to be another version of Yuto Sakurai, and no mention is made about what happened to that version's Deneb.
• Why Did It Have To Be: He's very afraid of ghosts, as revealed in #29.
• You Need to Get Laid: He once asked Urataros for dating advice to give to Yuto.

Tropes exclusive to them as Kamen Rider Zeronos

Altair Form!

Vega Form!

Charge and Up!

• All There in the Manual: The existence of Zeronos cards that have a Altair Form side and a Zero Form side was only hinted with the CSM release of the Zeronos Belt, which came as part of the set.
• Badass Cape: Vega Form sports an cape, and can still blast their enemies very well.
• Brought to You by the Letter "S": (A)ltair,(V)ega, and (Z)ero which are visible on both their corresponding Zeronos cards, the ZeroLiner's cars, and their Finishing Moves.
• Brutish Bulls: He's themed after a bull, and is capable of fighting well like Den-O, though their personalities are far from brutish.
• Cool Bike: The Machine ZeroHorn, a motorcycle based off the Honda XR250, which, much like the Machine DenHorn, serves as the control unit for the ZeroLiner. It can also accept Zeronos cards in lieu of a Rider Pass.
• Cool Train: The ZeroLiner, which is a super-powered steam locomotive, and much like the DenLiner, has the ability to travel time as well. It also has two train carts that have a drill and helicopter respectively.
• Deadly Upgrade: By default, all of the Zeronos cards cause his future self to be erased, which is bad enough, but the Zero Form cards erase his present self from other people's memories as well.
• Finishing Move:
  • ZeroGasher: While Zeronos is in Altair Form, both of this weapon's mode's finishers take on the form of a green A.
    • Bowgun Mode: Grand Strike: Zeronos fires a wave of energy against his target.
    • Sabre Mode: Splendid End: Zeronos slashes his target with a wave of energy.
  • Denebick Buster: Buster Nova: Fires a Rider Shooting that recoils its user.
• Fuel Meter of Power: He has a very limited supply of Zeronos Cards and has to make his transformations count.
• Jack of All Stats: Altair Form, one of the forms Yuto can assume, is less powerful than the Vega and Zero forms, but is more balanced in other areas to compensate.
• Lightning Bruiser: Zero Form, one of the forms Yuto can assume, is Zeronos' Super Mode, which is slightly less powerful compared to Vega form but more agile overall.
• Mighty Glacier: In Vega Form, Zeronos is slower compared to his other forms, but has the highest attacking power of them all.
• More Dakka: When in Vega Form, Zeronos has a lot more ranged options to deal with his opponents, especially when combined with the Denebick Buster.
• My Hero, Zero: Is called Zeronos, and its users are a Jerk with a Heart of Gold and a Nice Guy respectively.
• Powers via Possession: Unlike Den-O, only one of Zeronos' forms requires Deneb to possess him to access it.
• Red Is Heroic: Zeronos's Zero form has heavily rusted armor to the point where it manages to make the armor look red-colored, but it's Zeronos' Super Mode for a good reason.
• Shoulder Cannon: Vega Form has multiple cannons on his shoulders called the Zeronos Nova.
• Swiss-Army Weapon: ZeroGasher. The Sabre Mode is a BFS, Bowgun Mode is The Straight and Arrow Path, and Denebick Buster is a Talking Weapon.
• Transformation Trinket: The Zeronos Belt, which uses Zeronos Cards to transform into either Altair Form, Vega Form or Zero Form.
• Un-person: The cost of using Zeronos' powers, due to not being a Singularity Point. The more cards he uses, the more his and Sakurai's existance in people's memories are erased, subsequently erasing them from reality itself. The first signs of this was the fact that Sakurai had disappeared just before his wedding with Airi, with no one (including the latter, except for Ryotaro), remembering him since. That being said, this seems to have been mitigated after the series with Yuto using the Zeronos cards without any issue.
• The Unreveal: It's not known what happens if the yellow side of a red Zeronos' card is used with the Zeronos belt. All it's known is that using it with the toy versions produces the same sound as achieving Vega Form, but any differences is not known.

Tropes applying to Kamen Rider Zein

Kamen Rider Zein

Portrayed by: Tōru Ōkawa (Zein Driver voice), Kenya Saitou (suit)

The Rider based on the eponymous AI, Zein. Yuto Sakurai is assigned to transform into Kamen Rider Zein, an omniscient and omnipotent dimensional warrior powered by an Artificial Intelligence of the same name obsessed with eliminating evil at any cost. However, this Yuto appears to be an entirely different person than the one we are familiar with, instead he originates from a Bad Future where he did not fight for the one he loved.

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• Alternate Self: This Yuto Sakurai comes from an alternate Bad Future where he didn't fight for Airi's sake and something tragic befell her.
• Ascended Meme: For his 33rd birthday, Yuichi Nakamura made a tweet about himself wearing twenty-three rider belts on him, with comments comparing it to Kamen Rider Decade Complete Form and Ohma Zi-O. In Kamen Rider Outsiders, he becomes Kamen Rider Zein, which essentially combines the powers of all Riders bestowed on him like Decade and Ohma Zi-O.
• Bad Future: He comes from an alternate future where he Did Not Get the Girl and suffered tragic circumstances. It's implied humanity "went out of control" somehow, too.
• Became Their Own Antithesis: This Yuto goes from the hothead with a heart of gold who constantly berates his Imagin partner like his main timeline counterpart to a cold-blooded, nihilistic Knight Templar who seems to believe humanity is a lost cause as a result of tragic circumstances changed him for the worse.
• Beware the Superman: Even more so than the likes of Decade and Ohma Zi-O, given that he can Power Copy the Finishing Moves of all Kamen Riders and he serves as Zein's enforcer to carry out the complete extermination of every single Kamen Rider villain to ensure its totalitarian utopia becomes reality. The first thing Yuto does as Kamen Rider Zein is beating Banno within an inch of his life through Muteki Gamer's finisher, reducing him into a whimpering wreck hopelessly trying to escape with his life before turning him into a human pincushion with Xross Saber's Haou Xross Sei Retsuzan. Matters not helped by the fact that Yuto himself is more than willing to oppress mankind with the power of Kamen Riders to further Zein's end goal, until Brain talked him out of it.
• Broken Pedestal: To Brain. He didn't take too well with him playing along with Zein's plan in oppressing humanity with the power of the Kamen Riders. And his tragic backstory from his Bad Future isn't helping anything either.
• Casting Gag: Yuichi Nakamura once again portrays a Fallen Hero whose turn to villainy was a result of losing their significant other. Just like Zabil, the alternate Yuto Sakurai abuses the power of another hero to his personal gain. The only difference is that while Zabil takes on the form of Evil Trigger, who is a Mirror Match of the being whose powers he stole from, Yuto as Zein transforms through the belt that incorporates technology from Zero-One, gimmicks from Decade created by a character from Revice. Said Rider resembles a villain from Kuuga^{In this case}N-Daguva-Zeba, the show's Big Bad.
• Corrupted Character Copy: As Kamen Rider Zein, Yuto is one to Takeshi Hongo, the original Kamen Rider himself. Hongo has been the symbol of justice when he choose to use his newfound powers to protect the world from Shocker, who were responsible for altering his body with cybernetic implants. The alternate Yuto Sakurai comes from a Bad Future where he lost his loved ones, and is chosen by Zein to take the mantle of the namesake Kamen Rider, using the powers of every Kamen Rider to terrorize humanity into capitulation to Zein's new world order. In short, Yuto is everything what Hongo could have been like if he had sworn loyalty to Shocker rather than protecting mankind.
• Evil Counterpart:
  • To main timeline Yuto, and rightfully so. The former fought as Kamen Rider Zeronos, while at the same time having to risk his future self's existence (and his own) as a result of using many of his Zeronos Cards as well for Airi's sake. The alternate Yuto comes from a Bad Future where he has lost everything and was chosen as Zein's host in order to exploit the power of every Kamen Rider to subjugate humanity as Kamen Rider Zein. Given how the main timeline Yuto once tried to kill Sougo to prevent him from becoming Ohma Zi-O, this Yuto, on the other hand ends up walking on the same path as the Overlord of Time.
  • To Tsukasa Kadoya, both use cards containing the power of Kamen Riders. Decade's Rider Cards draw power from their A.R. World counterparts of every Heisei main Rider. The Zein Cards are Evil Knockoffs of Decade's cards where all of the main universe Kamen Riders gave their powers to Zein, and once used, that Rider and their associated powers are permanently erased. Yuto also embodies what Tsukasa would be like if he took his role as the "Destroyer of Worlds" more literally and figuratively for the wrong reasons.
• Fallen Hero: He used to be Kamen Rider Zeronos and considering that he's from a Bad Future where he loses Airi, he willingly allowed himself to become Zein's enforcer to exterminate all villainous Riders.
• Final Solution: He wants humanity to be exterminated to ensure his Bad Future doesn't occur, viewing them having gone out of control because of their capacity for malice.
• Grand Theft Me: Yuto's body is hijacked by Zein after the former is spurred by Brain's words into a Heel–Face Turn.
• He Who Fights Monsters: This is how Brain calls him out for siding with Zein, the fact that he's willing to oppress humanity with the power of Kamen Riders to expunge all malice does not excuse him from becoming the same kind of evil he's opposing.
• Heel–Face Door-Slam: At the end of #4, Brain manages to talk Yuto down and convince him to disarm, only for Zein to directly possess him.
• Humans Are Bastards: His overall worldview and given his origins from a Bad Future, he became the willing host for Zein to enforce its idea of order.
• Hypocrite: He lectures Brain and Ecole about how a villain can turn good and how a hero can turn to The Dark Side, when he actually goes on the latter path. The extent of his own hypocrisy rears on its ugly head when he nearly kills Horobi and the Ark, which could have cemented him into a straight up villain worse than even Banno of all people.
• I Let Gwen Stacy Die: The Airi in his timeline suffered a tragic fate, and the circumstances behind it remains ambiguous. It ultimately led him to becoming Zein's new host.
• Irony: In Kamen Rider Zi-O, he traveled to 2018 to prevent Sougo from becoming Ohma Zi-O, a tyrant who rules over a Bad Future by drawing the powers of the riders before 2068. In Kamen Rider Outsiders, this version of Yuto Sakurai assists with Zein to eradicate all the evil by defeating all Kamen Riders, both good and evil, and to impose his authoritian rule over humanity, essentially becoming Ohma Zi-O in name, and it's even implied that Sougo consented to giving his powers to Zein as well.
• Jumping Off the Slippery Slope: Narrowly avoided in episode 4. If not for Brain's intervention, Yuto could have completely crossed the line by killing both Horobi and the Ark, as destroying the latter won't eradicate malice so long the Ark can escape its host body by storing itself on the internet and will continue to sustain its existence so long humanity still has the capacity for evil. Killing Horobi, on the other hand, becomes this trope.
• Kill All Humans: Yuto implies this is the reason he came to this timeline. In his Bad Future, humanity went out of control and to him, Horobi's inability to exterminate them was to blame.
  Yuto: I came to return everything to zero.
• Knight of Cerebus: This Yuto is cold-blooded, murderous, nihilistic, and somber; a far cry from the fiery temper and heart of gold of his prime counterpart. In his introduction as Kamen Rider Zein, he shows no remorse at beating up Banno like a wild animal, deservingly so given his notoriety of being the vilest villain in the franchise's history. The real kicker, he is more willing to cross the line for the benefit of a greater good when most heroic Riders are not supposed to. The alternate Yuto serves as a cautionary tale of how a great tragedy can turn a hero into becoming the same kind of monster they're fighting.
• Make an Example of Them: His brutal beating of Banno is meant to put the Ark and Foundation X on notice. Ecole is visibly terrified at the sight of Zein's dominance.
• Mirror Character: As Kamen Rider Zein, Yuto has more in common with Aruto when he transformed into Ark-One and both of them had to fight Horobi at one point. Yuto comes from an alternate Bad Future where tragedy befell Airi Nogami and most likely haven't moved on from her fate ultimately led him to become Zein's willing host. Zein wants nothing more but to eliminate Ark and all the human malice associated with it, even if it destroys Horobi's Humagear body, although Zein fails when Brain shields the Ark-possessed Horobi only for Tachibana to finish the job. While Aruto snaps when Horobi kills Is in front of him, then tricked by As into using the Ark-Driver to become a new Ark himself to take out Horobi personally, only to inadvertently kill the latter's son, Jin, who likewise protected his father.
• My God, What Have I Done?: Thanks to Brain's pleas getting through him, Yuto realizes he went too far, narrowly avoided in Jumping Off the Slippery Slope, sparing Horobi (and the Ark). But Tachibana would go on to destroy the Ark anyway, followed by Zein possessing Yuto, denying him a chance to fully redeem himself.
• Noodle Incident: In #4, Yuto implies the humans of his world "went out of control" and that Horobi was linked to it.
• Pay Evil unto Evil: He absolutely shows no remorse in turning Banno into a Human Pincushion so he can make an example of the Outsiders. Doubly so since Banno himself is one of the vilest Kamen Rider villain in recent history; unlike Go who kills his father as revenge for the abuse he put his own family and creations through, the way Yuto victimized Banno is a step too far that is hardly played for catharsis, which is basically a fearmongering tactic to put the Ark and Foundation X on notice. And he is almost close into destroying the Ark along with Horobi, which is already an act of Jumping Off the Slippery Slope in and of itself had Brain never called him out for his cruelty.
• The Quisling: He willingly plays along with Zein's goal of exterminating humanity because that the humans in his Bad Future have gone out of control.
• Running Gag: Sixteen years later, this version of Yuto gets a massive power boost by becoming Zein's host. Yet even after switching to Progrisekeys and Rider Cards, he's still unable to make full use of his powers and fulfill his purpose without slowly burning away another set of plot-significant cards.
• Shadow Archetype:
  • The main universe Yuto spends his appearance in Kamen Rider Zi-O for two episodes trying to kill Sougo, fearing his potential to become Ohma Zi-O and doom the timeline, but eventually changed his mind after witnessing Sougo's conviction. Come to the third episode of Outsiders, this Yuto displays himself as the enforcer of Zein's will through the titular Rider form, as not only he can use a plethora of past Rider powers like Zi-O, but actively plays along with the namesake AI's authoritarian goals, hence seeing him slowly walking the same path as Sougo as Ohma Zi-O.
    • Related to above, Sougo gains the power of Ohma Zi-O after his friends (the ones he treasured the most) died but relinquish it to reset the entire world back to 2018 to live a second life with them again over accepting his fate as a ruler, thereby returning the past Riders' powers to their owners. Yuto loses his loved ones and by that point deems mankind as a lost cause, using the past Rider powers to help Zein establishing order. In short, the alternate Yuto is also Sougo if he accepted his destiny as Ohma Zi-O out of grief for his lost friends instead of trading it for a second chance in normal life.
  • To Heart, if he were to be more genocidal and vengeful against humanity as a result of the abuse Banno put him through, becoming no different than his tormentor. Of all the Roidmudes, Heart is the most morally principled and a role model to his kin, he comes to respect the Kamen Riders, including Shinnosuke during their run-ins. Whereas Yuto lost all faith in humanity in his timeline and exploits all Rider powers so that Zein can Take Over the World, in essence becoming the same evil he despised the most as Brain pointed out.
  • He is also this to Banno of all people. The No-Holds-Barred Beatdown he gave to the Mad Scientist is a karmic role reversal of the latter's physical abuse of Heart, and Banno represents what the main timeline Yuto would be like if his physical abuse towards Deneb is not played for humor.
• Shoot the Dog: He was nearly an inch away from killing both Horobi and the Ark in episode 4, which by doing so could've sent him straight into full-blown villainy if Brain didn't took the killing blow meant for Ark-Zero.
• Straw Nihilist: He believes that humanity is beyond saving considering the tragic circumstances that befell him in his Bad Future, and decides to take it upon himself to return everything back to zero.
• Uncertain Doom: Not him, but Airi's fate in his Bad Future is left ambiguous as of now. The fact that something bad befell her made Yuto snap.
• Walking Spoiler: It's very difficult to discuss everything about what happened in his timeline, as well the fates of his Airi and Deneb.
• Woobie, Destroyer of Worlds: He becomes Zein's willing host to enslave humanity with the power of all Kamen Riders, believing that humanity as a whole is beyond saving given the circumstances of his Bad Future.

Tropes associated to Kamen Rider Zein:

Zein Rise!
Justice. Judgement. Seigi. Zein.
Salvation of humankind.

• All Your Powers Combined: As Zein, he can wield the Haouken Xross Saber and the power of Hyper Muteki, both of which are already coalescences of every ability in their home series. He also carries Zein Cards, artificial copies of the Rider Cards that otherwise him to otherwise tap into the power of every other Kamen Rider. Unfortunately, this aspect of Zein is on borrowed time, as every use of an individual power will also destroy it.
• Composite Character: Zein's power set is derived from the Progrisekey used by Zero-One and his contemporaries as a means of transformation, while combining the Power Copying abilities of Kamen Rider Decade through the Zein Cards. Alternatively, Zein is cast in the same mold as Kamen Rider Ark-One with the power sets of Decade Violent Emotion and Ohma Zi-O into one Rider.
• Corrupted Character Copy: Of Kamen Rider Decade. Tsukasa Kadoya is an amnesiac man who has no memory of his past and other A.R. World Riders somehow revile him as the "Devil" whenever they encounter him due to having once associated with a multiversal conquering organization known as Dai-Shocker. The Yuto Sakurai from an alternate Bad Future having lost everything he cares about comes into the present day to carry out Zein's will to expunge humanity. Zein's ability to use mostly the abilities of Kamen Riders' final forms brings to mind Decade Violent Emotion, who can use the arsenal and powers of other Riders without transforming into the Rider whose power he used from Rider Cards.
• The Dreaded: Zein is basically an artificial, present-day version of Ohma Zi-O and his very presence alone stirs dread, eerie and terror for the villains. He is able to reduce Banno into a whimpering wreck after beating him within an inch of his life and the brutal beating he gave to the Ark left it completely petrified in fear.
• Evil Knock Off: The Zein Cards are this to Decade's Rider Cards, denoted by Zein's symbol being marked on the back instead of the one for whoever is on the card. Every heroic Rider have given up their powers to Zein in hopes of cleansing the world of evil, putting their reliability into question. Once the Zein Card is shredded, that Rider and their associated powers are permanently erased due to the fact that the Zein Driver is integrated with Kamen Rider Chronicle's data.
• Finishing Move:
  • Justice Order: Zein scans (and shreds) a Final KamenRide card, allowing him to copy one of the corresponding form's finishers once.
    • Ex-Aid Hyper Muteki: Zein performs the Hyper Critical Sparking, augmenting it with his Super-Speed to strike the target from all directions before pummeling them into the sky.
    • Xross Saber: Zein draws the Haouken Xross Saber and performs an abridged version of the Haou Xross Sei Retsuzan, skewering the opponent with all 12 Seikens.
    • Blade King Form: Zein performs Four of a Kind/Four Cards by summoning the King Rouzer along with four Category King cards: Evolution Caucasus ♠K, Evolution Paradoxa ♥K, Evolution Giraffa ♦K, Evolution Tarantula ♣K, and a Category Ace card: Change Beetle ♠A. Zein loads the cards into the King Rouzer and charge towards the card projections to deliver a downward slash.
• Good Powers, Bad People: Lampshaded by Brain, Zein harbors the power of all known heroic Riders to date (in fact, Saber's attack utilizes 10 Seikens, known as Holy Swords), but his brutal usage of them makes it clear that he is nowhere as benign as their original owners. Even less so when the namesake AI takes over.
• "Have a Nice Day" Smile: Zein's Rider logo resembles a smiley emoticon drawn like this: (^v^), given the darker context of Zein's authoritarian goals, it gives the impression of a Perpetual Smiler.
• Holding Back the Phlebotinum: While there's no known cost for him to use the Zein Driver, the Zein Cards that link to the device get shredded after their initial use, requiring him to ration their various Story Breaker Powers carefully.
• Homage: Kamen Rider Zein's design more or less bears a striking resemblance to N-Daguva-Zeba. Matters helped when the man who developed the Zein Driver happens to transform into a Rider based on Kuuga Ultimate Form and is a die-hard Kamen Rider fanboy.
• Judge, Jury, and Executioner: As Zein's host, Yuto is the executioner while transformed into Kamen Rider Zein, while the eponymous AI is the one who judges anyone who it sees as a threat to the human race and gives the final verdict if they are guilty of being "evil". Even better that the Rider's finishers are called Justice Order, further emphasizing Zein's twisted idea of order.
• Light Is Not Good: Kamen Rider Zein is adorned with a platinum white armor and gold accents. But the way he dominated Banno is anything but heroic.
• Villain Killer: As Kamen Rider Zein, he reduces Banno into a human pincushion destroying his Humagear body in the process. He manages to beat the Ark within an inch of its life leaving it enough to be weakened allowing Garren to unlock King Form and obliterate Ark-Zero when Yuto hesitates.