This is a partial character sheet for Kamen Rider Build. Visit here for the main character index. Subjective trope and audience reactions should go on the YMMV page.
- Artificial Zombie: For all intents and purposes, a Hazard Level One Smash is this. According to Night Rogue, they die instantly on the operating table, meaning the Smash is basically their corpse animated by the Smash essence.
- Color-Coded for Your Convenience: Guardian robots that have been taken over by Faust are either dressed completely in black or have had their face plates blasted off.
- Cyanide Pill: The bottles used to store and release Smash essence can also be used by operatives to completely disintegrate their bodies to avoid capture. Later varieties of Smash start to enforce the trope by disintegrating the host's body if they're destroyed without special precautions.
- Decon-Recon Switch: Of the classic Nebulous Evil Organization of the Showa era. Amidst the backdrop of societal breakdown and national tensions caused by the Sky Walls, Faust's Monster of the Week schemes begin to appear increasingly quaint and suspect, with the whole thing eventually turning out to be a sham perpetrated by the real Big Bad. The middle half of the show discards Faust outright in favor of focusing on more grounded villains in the form of other nations with their own Riders and a powerful Mega-Corp. The last quarter of the show then brings things back around to where they started when those antagonists turn out to have all been pawns of the real villain too, and having gotten everything he wanted out of the war, he starts using his newfound power and resources to do experiments that end up being just like what he was doing with Faust.
- To Shocker from the original series, as both are terrorist organizations that create their monsters through capturing ordinary humans and conducting experimentation on them.
- Both Night Rogue and Blood Stalk are direct expies to Mashin Chaser due to them being a mechanical-looking Kamen Rider-like rivals to the main rider before they gain their proper rider forms later in the show. However, while the former turned to the side of good just like Chase, the latter is a full-blown villain through and through.
- Evilutionary Biologist: One of their goals is the creation of an Ultimate Lifeform, and the Smash are a means to that end. The Smash themselves have almost nothing to do with it, though, as Night Rogue's plan is to mass produce Kamen Riders for military use, and Stalk already is the ultimate lifeform.
- Far East Asian Terrorists: Based in the Touto region of the former nation of Japan.
- Flawed Prototype: Subverted: the Smash are failed prototypes of Night Rogue's real end goal, but Stalk likes them just fine, both as refineries for his FullBottles and in their own right as a means of having humanity tear itself apart.
- Gas Mask Mooks: Scientists under Faust's employ all wear them while experimenting on their "subjects". It's one of the few clues Sento has about them and what clued him that Ryuga might be telling the truth.
- Green Aesop: Night Rogue and Blood Stalk represent cruder sources of energy like coal and oil in contrast to Kiryu's "purified" powers.
- Green Lantern Ring: The emissions from their Transteam guns have a lot of usages derived from studying the various mutations and powers created via Nebula Gas.
- I Fight for the Strongest Side: While originally conceived as a paramilitary force for Touto, they have since allied with whoever is willing to fund and house them including Hokuto, Seito, and most frequently, Namba Heavy Industries.
- Laser-Guided Amnesia: Amnesia is a frequent side effect of Nebula Gas exposure, which Faust takes advantage of to cover their tracks by ensuring their victims get a heavy enough dose to forget everything that happened while captive. In one particular case they go so far as to wipe a man's entire memory so he can't reveal what he knows about them. But the amnesia isn't permanent.
- Make My Monster Grow: Using Devil Steam to give a Smash a second dose of the gas used to transform them will cause them to grow to giant size.
- Meaningful Name: The organization's name of course references Faust, a story about a scholar that sold his soul for magical powers. Quite fitting for a group that turns humans into monsters. Their founder was nicknamed "The Devil's Scientist", a clear reference to Faust.
- The name becomes even more meaningful when it comes to light that Evolt was directly behind the events that lead to its foundation, being the almost literal devil Faust's members unknowingly struck a deal with.
- Mecha-Mooks: Since all Guardians were created by the Namba Corporation, Faust's bankroller, Faust's generals can hijack any Guardians in the area to serve their own needs. They additionally have a set of Guardians that work for them full-time, distinguished by their broken faceplates and all-black clothing.
- Monster of the Week: The Smash subvert this; while they are there to be a monster for the heroes to battle, fighting them is not the main focus of the episodes, and some are only onscreen for a few minutes before being defeated. "Smash-of-the-Week" are eventually phased out entirely in favor of Rider battles, only to start making a comeback in the last act with the Lost Smash.
- Nebulous Evil Organisation: They are a secret terrorist group that's responsible for the creation of Smash through human experimentation.
- Offscreen Villain Dark Matter: Averted: They get a stead supply of Nebula Gas needed to make the Smash because their bases are built on top of places that it constantly emerges from the Skywalls. Faust also gets its funds from Namba Heavy Industries, which gives their owner blackmail material on the organization. In the last act, Faust takes over Namba, and by extension Seito and Hokuto, giving them an entire zaibatsu and an entire nation's resources to play with.
- Playing with Syringes: They have no moral problem with turning ordinary folks into aggressive monsters for their own goals. In episode 1, we can see that they got so good at it, their lab looks more like an assembly line.
- The Power of Hate: Hazard Levels are usually dependent on a person's level of strength and willpower, but they can be raised more easily by increasing one's aggression.
- Psycho Prototype: Smash are the first step in FullBottle production, and essentially act as lesser prototypes for the powers the purified bottle will eventually grant. The Lost Bottles that Night Rogue and Blood Stalk, and later the Lost Smash, use are eventually revealed to also be this compared to the other FullBottles, as they make the user more violent and susceptible to manipulation.
- Turned Against Their Masters: Newly created Smash often try to escape and take revenge upon their creators, but Night Rogue is always on-site for the express purpose of beating them into subservience.
- Was Once a Man: The Smash they create are this, having been humans that were experimented on until they became monsters.
- Well-Intentioned Extremist: Night Rogue's goal is ultimately to create a superhuman fighting force to protect Touto from its neighboring rivals and foreign nations that want to annex it even if it means deferring to a man who doesn't care much about his country and just wants his own Kamen Riders. Blood Stalk is less well-intentioned and more extremist.
Portrayed by Jun Watanabe (suit), Kensei Mikami (voice, I), Yuki Ochi (voice, II)
A sinister figure behind the terrorist organization "Faust", and subsequently responsible for the experimentation that turns humans into Smash. A cold-blooded villain, he takes great pleasure in the suffering of his "guinea pigs".
For more information on their human identities as Gentoku Himuro and Nariaki Utsumi respectively, go here.
- Bat Out of Hell: He has a bat motif and Sento calls him "bat man" while explaining what little he remembers of his past.
- Big Bad Duumvirate: With Juzaburo Namba, who's providing funding to Faust. They have different ends, but the same means: starting a war between the three factions of Japan. Night Rogue wants Touto to emerge triumphant from the resulting conflict he feels is inevitable, while Juzaburo is simply a war profiteer seeking to make money on weapons deals from it. However, gradually they start to separate and begin opposing each other.
- But for Me, It Was Tuesday: When Sento confronts him about the experiments, Night Rogue bluntly responds that he won't remember every guinea pig's face. He is later revealed to be lying.
- Chest Insignia: He has a giant yellow bat on his chest.
- Dark Is Evil: Is the apparent leader of a terrorist faction and looks like a demon.
- Disc-One Final Boss: He's initially touted as the villain of the show, but he does rather little as Night Rogue compared to Stalk.
- Evil Laugh: He has a profoundly creepy and distorted-sounding one.
- Evil Sounds Deep: He speaks in a deep, distorted voice.
- Finishing Move: The Transteam Gun comes with several, depending on its configuration, such as the Steam Break in pistol mode, and the Steam Shot in rifle mode. Night Rogue, uniquely, can perform an attack similar to Knight's Final Vent.
- The Heavy: Even knowing that Faust is backed by Namba Heavy Industries, Night Rogue is the one who moves Build's early plot along with his actions.
- Hell-Bent for Leather: His suit from the waist down evokes this.
- I Have Your Wife: One of many tactics he employs to keep people under his thumb is threatening their loved ones. One such person is Masahiro Nabeshima, who was blackmailed into framing Banjo Ryuuga so he could be spirited away for Smash experimentation.
- Kick the Dog: While taking all of Build's bottles in episode 10, Rogue specifically points out the Gorilla bottle Sento used to defeat the Burn Smash, simply to rub salt in the wound that Sento still blames himself for not being able to save her.
- Knight Templar: While he is an extremely awful person, his ultimate goal does seem to be for Touto to emerge victorious from a war he believes to be inevitable.
- Lack of Empathy: Night Rogue just doesn't care at all about the people he hurts, approaching his organization's experiments and the resulting fallout of what happens to his "guinea pigs" with cold indifference. He even explains the details of "Hazard Level One" in a cold professional monotone.
- Obviously Evil: Not a good guy by any stretch of the imagination and looks the part, too.
- Power Gives You Wings: He can sprout wings to fly.
- Shout-Out: Like many recurring instances of the Bat/Spider/Cobra trio, he's one to Bat Man, the second Shocker monster from the original series.
- Shut Up, Kirk!: His counterargument to Sento's Kirk Summation on how science can be a benevolent force for humanity is a quick punch to his spine.
- Sinister Shades: The big yellow bat symbol on his face is a partially opaque visor that covers the real "eyes" of his suit.
- Slouch of Villainy: The first time we see him through Sento's flashback, he's kicking back watching over Sento being modified in an incredibly tacky chair.
- Smug Super: The very first thing he does upon meeting Sento is correct him on his name.
- Super Smoke: Can turn into smoke at will, mainly using this ability to pull off Stealth Hi/Bye maneuvers.
- Superpower Lottery: The Bat Full Bottle gives him the ability to cling to walls and fly in addition to a comprehensive suite of enhanced strength, durability, and speed.
- Spell My Name with an "S": Could be written down as Nitrogue, Knight Rogue or Night Rogue. Ganbarizing cards show it as being Night Rogue.
- Sword and Gun: He uses the Transteam Gun and the Steam Blade in combat.
- The Bad Guy Wins: It would have been hard for episode 10 to go much better for Night Rogue than it did. Every single Full Bottle except Dragon and Lock falls into his possession, as well as the Pandora Box itself, and his father suffering a heart attack earns him a promotion.
- Unskilled, but Strong: Relatively speaking. While Rogue is a decent enough fighter, his combat experience pales in comparison to Stalk's, possibly even to Sento and Ryuga's. What skills he has aren't enough to maintain his advantage once the Hazard Level of his opponents rises to where they can properly threaten him.
- Villain Forgot to Level Grind: The fact that the villain cannot level grind is a major plot point. If the Transteam System could grow in strength like the Rider System can, Night Rogue's schemes would be much less elaborate. First he ends up being the victim of The Worf Effect to Cross Z during the latter's debut. Then we see just how much of a disadvantage this is for him in comparison to Build in episode 20, when not only does he find himself on the receiving end of a Curb-Stomp Battle against Build's RabbitTank Sparkling form, but Build is able to No-Sell him in that form.
- Villain Protagonist: Of the 3-episode ROGUE Blu-Ray miniseries that details his Start of Darkness.
- War for Fun and Profit: Desires to set off a war between the three sides the Skywall split Japan into, with the intent that Touto come out on top.
Evolt / Blood Stalk / Kamen Rider Evol
Portrayed by Tetsuo Kanao (voice), Kazuya Okada (suit)
Warning: Due to the sheer number of spoilers associated with this character, all spoilers are left un-marked. New viewers beware.
Another figure behind Faust, an enforcer and strategist that carries out his duties with a disturbingly flippant attitude. Openly refers to himself as Faust's strategist.
In truth, Stalk is just another name for Evolt, an extraterresial lifeform from a distant star that came to Mars with the Pandora Box and used its power to turn the once-green planet into a lifeless wasteland before being defeated in a final duel with the Martian queen Vernage, who destroyed his Evol Driver and left him a helpless mass of sludge. Evolt lay dormant for untold millions of years before an unmanned probe from Earth arrived to the red planet, prompting Evolt to send part of his being along with the probe on its return. The rest of him infected the astronaut that came to Mars next, Souichi Isurugi, taking over his body to use as Evolt's new host as he planned to reclaim his lost half, rebuild his shattered Driver, and bring about the destruction of Earth.
- 24-Hour Armor: Unlike Night Rogue, who seems to only wear his armor when needed, Evolt prefers to wear the Blood Stalk armor at all times whenever he is around other villains, to the point it is implied even members of Faust have no idea who he is under the mask. He eventually becomes more lax about this policy after his identity comes out, but still prefers wearing the suit nearly all of the time.
- A Form You Are Comfortable With: After he completes the Evol Trigger, he no longer needs a host body and can shapeshift into anyone. He decides to default to the form of Soichi.
- Alien Invasion: He is eventually revealed to be an alien invader attempting to wipe out all life on Earth, as he did to Mars in the ancient past.
- Aliens are Bastards: His true identity as Evolt is an alien whose idea of fun is destroying all life on planets and who spends most of the show possessing an innocent man to make him do horrible things while fully conscious of everything.
- Ancient Evil: It is not clear exactly how old Evolt is, but he has been lying dormant ever since the destruction of the Martian civilization, meaning he is millions of years old at least, and Mars wasn't the first world he has destroyed.
- Archnemesis Dad: As it turns out, the alien that accidentally sired Ryuga was a piece of Evolt, effectively making him Evolt's son, which Evolt eventually acknowledges. This doesn't make Evolt any kinder to him than anyone else and he repeatedly tries to murder him.
- Ax-Crazy: And how! He takes his sadism to insane levels to the point that his fellow Blood Tribe members have becoming fed up of it.
- Back from the Dead: In the Cross-Z V Cinema, Evolt manages to recover from being sacrificed for the New World by attaching a piece of himself to Ryuga which he could regenerate from if it ever came into contact with Pandora's Box.
- Becoming the Mask: Subverted: Stalk's voice changer is initially used to obscure his identity, but after the first reveal about his identity he continues to use it while wearing the suit, unlike almost every other case of a voice changer-using character in the franchise. The second reveal comes with the Wham Line that shows the deeper voice is Evolt's actual voice, and he was never using the voice changer at all. It is played with some more when even after acquiring his own body, Evolt prefers Soichi's shape, and even mimics his voice while in that form, but this changes nothing about his personality.
- Berserk Button:
- His plans being derailed. Evolt is very cunning and often in control, but the moment something unexpected throws a wrench in his works and sets them back, Evolt does not take it well.
- A 'lesser lifeform' defeating him is another thing Evolt cannot stand and any genuine loss to an 'inferior' opponent will royally tick him off.
- Big Bad: Evolt is eventually outed as the true one of the show, standing above Faust, the three nations, and even Juzaburo Namba. All of the other factions, heroes and villains alike, dance to Evolt's tune as he goads and manipulates them to reach ever-greater heights of destruction in fighting one another, all for the sake of achieving the deadly purpose of the Pandora Box.
- Bishōnen Line: By his race's standards. It's eventually revealed in the Cross-Z V-Cinema that Evolt's final form is simply himself as he appeared on his home planet, just wearing the Evol Driver. It's the equivalent to if Build's final form was just Sento wearing the Build Driver.
- Bizarre Alien Biology: Evolt is a very strange organism to say the least, with biology like nothing on Earth and having more in common with a Blob Monster than anything else. This is a problem, as his venom is so unlike anything on Earth that it is impossible to cure.
- Blessed with Suck: The black Pandora Panel and Lost Bottles are secretly this. While having them makes Evoltable to warp between planets and consume their resources, their real function is to make him vulnerable to the white panel, which will use him as a Living Battery to merge Build's wartorn universe with another one and undo Evolt's reign of terror.
- Blob Monster: Evolt's true nature has shades of this, as his shape-shifting gives the impression of him becoming a mass of liquid and rearranging himself and the parts he separates from his main body assume the form of small blobs of material.
- Body Surf: Evolt first possessed Soichi on Mars, then surfed into Ryuga after he hit Hazard Level 5. Then he did the same to Sento when he reached Hazard Level 6.
- Broke Your Arm Punching Out Cthulhu: He shared a mutual one with Vernage back on Mars. While he did succeed in wiping out the Martians, their Queen proved powerful enough to defeat him in one final duel, leaving him trapped and nigh-helpless on the planet he'd destroyed.
- Brought Down to Badass: Twice. Fighting Vernage on Mars broke his Evol Driver in half and reduced him to just a helpless blob of goo, but even in this state he could amplify the strength of a human host to Hazard Level 5. When he manages to revive himself in the Cross-Z V-Cinema, he's reduced to only being able to use his Blood Stalk form, and even a deliberate juicing up from Sento only lets him reclaim Evol Cobra. He displays his true form after the battle, but his dialogue indicates that this is just his true shape from his homeworld rather than the universe-devouring Fever Flow.
- Cain and Abel: Evolt and Killbas don't get along. Both want to wipe out everything in the universe but Evolt wants leave himself alive while Kilbas just wants to destroy everything including himself, which ironically makes Evolt the Abel to Killbas' Cain.
- Catchphrase: "Ciao!"
- The Chessmaster: He refers to himself as a game master in episode 4. Despite his apparent laziness, everything he does is part of a carefully laid strategy, so much so that almost everything that happens in the first quarter of the series is one gigantic scheme of Evolt's coming to fruition, and that scheme is just the first step of his far grander one.
- Chronic Backstabbing Disorder: Nearly everyone Stalk works with is stabbed in the back somehow, a consequence of his playing every side and his plan being to eventually kill them all. Rogue is his favorite chew toy, who becomes aware enough of this status to thwart Stalk's backstabbing on occasion, but remains too blinded by his ambitions to avoid Stalk's continued manipulations. He ultimately intends to kill literally everyone, so loyalty is decidedly something he lacks.
- Consummate Liar: He lies so often that it really shouldn't surprise anyone anymore. Notably, the first episode of ROGUE reveals that he seemingly lied about Takumi Katsuragi being Faust's founder since it was shown that Gentoku did most of the groundwork and recruiting with one of those recruits being Katsuragi himself.
- Contrasting Sequel Antagonist: Despite having a lot of similarities on the surface, Evolt/Kamen Rider Evol easily differs a lot from Masamune Dan/Kamen Rider Cronus:
- While being just as much Faux Affably Evil, The Chessmaster, and an Archnemesis Dad as his predecessor, Evolt is presented as The Slacker and a Troll when interacting with others, while Masamune made sure he came across as an respectable CEO at all times.
- Both are Manipulative Bastards who managed to get practically all of the central characters in their respective story to unknowingly do their bidding in one form or another and waited until around the final stretch of their respective series to fully take up the position of the Big Bad. But whereas Evolt in Build is firmly The Man in Front of the Man from the very beginning as a major character, Masamune was The Man Behind the Man who started out as a relatively minor character in Ex-Aid; his true role in that series not being fully revealed until his show's endgame begun.
- In regards to Rider powers, Kamen Rider Evol is an alien horror whose central abilities revolve around black holes and space traveling, which greatly differs from Kamen Rider Cronus, who was an amoral human being that had the power to stop and even rewind time.
- Evolt could also be considered one to the Great Leader from the Showa Kamen Rider series. Both are supernatural forces behind evil organizations and nearly all of the problems faced by the heroes, but whereas the Great Leader was The Man Behind the Man to all of the terrorist groups he started up and let his minions face the Kamen Riders while generally not do very much himself, Evolt is The Man in Front of the Man who acts as a subordinate within each of the villainous factions he joins all while manipulating their leaders into unwittingly doing his bidding and is very proactive in engaging the heroes.
- The Corrupter: Through his Pandora Box and its Hate Plague, although with Nanba and Utsumi he didn't even need the Box. Evolt also feigns trying to corrupt Sento and Banjou by mocking their idealism, but corrupting them isn't the goal; manipulating them by implying he wants to is.
- Crazy-Prepared: Evolt put not one but two contingency plans to revive himself in place after he achieved his Phantom state, even though he believed himself to be invincible at the time.
- Create Your Own Hero: When Takumi Katsuragi tried to stop Evolt before his plans went into motion, Evolt instead wiped his memories, changed his face and raised him (under the guise of Soichi Isurugi) into Sento Kiryu in order to use him as a pawn in his plans. It worked for most of the series, but then Sento ends up becoming one of the main factors standing between him and ultimate victory just when his plans start to reach their end. What's more, the Genius Bottle, a completely unexpected variable in Evolt's plans and a vital key to stopping him, turns out to be only usable by the kind of person he raised Sento into, a hero of justice.
- Cruel Mercy: If anything could be considered Evolt's Fatal Flaw, it is his love of this trope. He could have opened the Pandora Box as early as episode 12 if he would just killed Nabeshima instead of wiping his memory with amnesia that turned out to be temporary. By episode 39 he came out victorious, completely and totally, but leaves the Riders and humanity as a whole alive when there is nothing that could stop him from killing them all because he wants to turn them into Lost Smash. This act of sadism allows the creation of the Genius FullBottle, the first thing to be a serious threat to Evolt, and his response is to double down and leave Sento alive with the intent of crushing his hopes first. He tops himself in episode 45 by letting his sadism ruin an assured victory twice in one episode: first by killing Shinobu slowly so that he has time to give his son a final hint, and then by forcing Sento to watch him destroy a planet and then bringing him back to Earth instead of just dumping him out in deep space, which gives Sento time to have the realization that lets him undo Evolt's hard work.
- Deader Than Dead: His final fate: he is not only killed but the merger of worlds means he is effectively been erased from existence. Except until he regenerates from the DNA he placed in Ryuga Banjou.
- Death by Irony: Evolt meets his end at the hands of the same person he molded into a hero Sento.
- Demonic Possession: Until he gets the Evol Trigger back and active again, Evolt has to use others as host bodies. He spends most of the show in Soichi, then has brief tenures in both Banjou and Sento's bodies before he reclaims the Trigger and stops needing a host. Once he's used to being complete, he can send out chunks of himself to possess others at will, at the cost of not being able to use Black Hole Form unless he's all in one piece.
- Dragon with an Agenda: Evolt lets each of the other villains take turns as the major threat while he plays their dragon, all the while advancing his own goals instead of theirs. The moment he's complete, he ends the facade brutally and effectively.
- Enemy Mine: Assists Build and co. in fighting against his Ax-Crazy Stronger Sibling Killbus. Cruel as he may be, Evolt at least has some sense of self-preservation while his brother just wants to destroy everything for fun.
- Enigmatic Minion: When we first see him, he is a mysterious enforcer for the Faust organization. It takes about a quarter into the series for his civilian identity to be discovered, and it is only around halfway through that his true identity is revealed along with the fact that he is the true antagonist of the series.
- Evil Cannot Comprehend Good: Despite his complex knowledge of the human mind, Evolt has difficulty understanding why Banjou would be so fiercely protective of Sento even after learning the truth behind Katsuragi's attempt to murder him. Even if he doesn't understand it, though, he's willing to use it as a tool to manipulate Banjou.
- Eviler Than Thou: Evolt proves to be this to every other villain with the possible exception of Bikaiser from the movie, from Night Rogue to Namba. Namba in particular gets a rude awakening when Evolt decides You Have Outlived Your Usefulness and wipes his faction out in short order.
- Evil Laugh: A deep, echoing sort of laugh that will haunt your dreams. All of them. It is mercifully rare. His Evol Driver does a totally psychotic one when he transforms. Even his EvolBottles are made to look like they're silently laughing whenever he turns the crank of the Evol Driver. Once he fuses the completed Black Pandora Panel into himself and cranks up the Black Hole Trigger to its version of Max Hazard On, it turns downright maniacal.
- Evil Luddite: If his rant towards Sento in episode 35 is to be taken at face value, Evolt believes that science making life more convenient leads to people taking things for granted and eventually getting wrapped up in war. Of course, given that he has spent the series trying to goad Sento into advancing technology for his own purposes, wants to anger Sento enough to raise his Hazard Level ever higher, and has gone out of his way to manipulate all sides into advancing warfare for his plans to wipe out all life, its best to take his lines with a grain of salt.
- Evil Is Petty: Evolt is this due to a combination of being both extremely narcissistic and incredibly vindictive. If his ego is bruised, he can't help but try to severely and sadistically punish anyone who bruises his ego. This is a Fatal Flaw of his and his biggest weakness, as it comes at the cost of his pragmatism.
- Evilutionary Biologist: He has spent over a decade fostering research into human exposure to Nebula Gas and the Rider System in hopes of creating a human body with a high enough Hazard Level to possess so that he can use his full powers through it. Once he is done with that scheme, he keeps indulging in the hobby, this time to create Lost Smash.
- Evil Mentor: Because Evolt's schemes need both Banjou and Sento to have extremely high Hazard Levels, he plays a mentor figure whenever they need a push to move forward.
- The ROGUE mini-series reveals that he was this with Gentoku and, to a lesser extent, Takumi Katsuragi as well. Ostensibly under the orders of Namba Heavy Industries, he stoked Gentoku's then fairly dormant influence from the Pandora Box, helping to turn him into the egotistical madman he was by the first episode and gave Katsuragi the necessary data on Nebula Gas to produce a stable Smash transformation, both of which directly led to the founding of Faust.
- Evil Prince: Since his brother is stated to be the "King" of the Blood Tribe, it could mean that Evolt has royal blood.
- The Faceless: Evolt swaps between several faces over the course of the show, and when he reveals his own it's so alien that it takes a flashback to Evolt on his home planet to confirm that it even is his real face. Even after his identity is revealed, he commonly uses the form of Soichi like an untransformed state, although his real untransformed state is identical to his Fever Flow form.
- Fake Defector: During the fight with Killbus in the Cross-Z V-Cinema, Evolt pretended to betray the heroes and attack Yui in order to get Ryuga angry so his Hazard Level would be raised to the point where he could use the Muscle Galaxy Fullbottle.
- Famous Last Words: In the last episode:
- Evolt: You think you can destroy me!? Like hell you will, you puny humans!
- And then in Kamen Rider Build: Final Stage:Evolt: So this...is the power of humanity... Then allow me to see this miracle you call the new world through till the end. Ciao...
- Fatal Flaw:
- His pride. He always believes that he is holding all the cards or is so much more powerful than everyone else (and is usually true), so he keeps the heroes alive partly as part of his plan and partly so that he can make them suffer. His plans do indeed go without a hitch for most of the series, but once it starts nearing the end stages, he starts finding the heroes harder to fight and his plans delayed more often, and the only way he knows how to deal with the frustration over it is to toy with the heroes more, which just gives them both time and motivation to get stronger and counter his plans.
- Wrath. Evolt cannot and will not tolerate having his ego bruised and will go to great lengths to make those who do so suffer...but in the process loses his pragmatism and gives his enemies openings to strike back.
- Faux Affably Evil: Both before and after The Reveal of his identity, Evolt is a much more casual and friendly antagonist than Night Rogue, though underneath all of it he is a cruel being whose plan involves wiping out all life on earth. He is also happy to backstab even his own allies, and will even go so far as to reveal information or aid the heroes on occasion, but it is always in service of his own ends.
- For the Evulz: While an exact motive for his Omnicidal Maniac ambitions has yet to be stated outright, it is heavily implied that this is at the root of his actions, given that his reaction to Utsumi going insane and becoming MadRogue is one of such great amusement that he reconsiders destroying the Earth.
- From a Single Cell: Episode 45 reveals that he can store a part of himself inside his Evol Driver which will eventually regenerate into a full body. Shinobu attempts to delay this by storing the Driver in a special container, but unfortunately, Evolt was smart enough to splinter off another segment which possessed Utsumi, rendering his effort moot. This is how Evolt managed to reappear in Build NEW WORLD: Cross-Z by planting a single cell into Banjou after being finished off by Build's RabbitDragon Vortex Attack Notably, this ability seems unique to him out of the Blood Tribe, as every other member of his species are killed far easier, even the far stronger Killbas. Banjo's Blood Tribe DNA is the only other thing that has this level of regenerative ability, which came from Evolt himself.
- Gone Horribly Right: His plan involved making the Riders heroes so that they'd gain strength for him to exploit in his own plans. He succeeded, but didn't count on them becoming powerful enough to actually oppose him and is ultimately killed by them.
- Grand Theft Me: For most of the series, he has been controlling Soichi's body due to his own body being destroyed. Later, he switches to Ryuga (in order to get back his DNA from him) and then Sento (in order to try and take advantage of his higher Hazard Level) before getting a body of his own. However, he later demonstrates the ability to splinter himself off to possess someone else, though doing so leaves him unable to use his full power until he merges back with the splintered part.
- Hazy Feel Turn: Leaves earth after Killbus is destroyed at the end of Cross-Z NEW WORLD, but there is no indication as to if he actually changed or just waiting until later to destroy earth.
- Hoist by His Own Petard:
- He is ultimately killed by the very Riders he created for his plans.
- His Doomsday Device is turned against him via the white panel and ultimately used to eradicate him from existence.
- Hidden Agenda Villain: Evolt manages to hide why exactly he wants Sento and Banjou to become stronger for most of the show, only making it clear when it is too late to stop him from taking their bodies.
- Humanoid Abomination: Possession by Evolt alters his host's physiology and gives them bizarre powers, to the point that they're stronger than the Blood Stalk suit on their own. There is also the whole 'possessed by an evil, ancient alien entity' thing. Once he becomes complete, he still chooses to appear human, but frequently reminds the audience he's only pretending to be one.
- Humanity Is Infectious: His time among humanity, his frustration at Sento's delays to his plans, and the direct threat to his life that Build Genius represents eventually lead to Evolt switching from performative mimicry to genuine emotions. It is Deconstructed by actually making him an even more dangerous villain, because he can now process emotions like anger and sadism. On top of that, because he can now feel anger he can now raise his Hazard Level and become even stronger. However, it also exacerbates his existing Fatal Flaw by making his anger at Sento sufficient that just killing him won't be enough to satisfy Evolt's need for vengeance, which only gives Sento more time to chip away at Evolt's plans.
- Impaled with Extreme Prejudice: Vernage defeated him in her Last Stand against him by running him through the Evol Driver with a energy BFS.
- I Need You Stronger: One of Evolt's many goals throughout the show is to raise Sento and Ryuga's Hazard Levels, as well as to raise Sento's technical knowledge of Driver creation to the point where he can repair the Evol Driver.
- Intrigued by Humanity: A horrifying example. After Utsumi going insane and joining him, he declares humanity to be too interesting to kill off and instead decides to conquer them and then kill them off. How much of this is true and how much is yet another manipulation is up in the air.
- Invincible Villain: Early on he holds back his true power because he needs the heroes alive for his plans, so most of his loses are because he wants them to win. It is only in the later half of the series that the heroes even begin to catch up to him. Unfortunately, it is also around this time that he gets back his Evol Driver and becomes Kamen Rider Evol, who outclasses all the heroes at the time of his debut, which he claims to only be a small percentage of his true power. Sure enough, every time it seems that the heroes are catching up to him, he manages to unlock more of his power and outclasses the heroes again. Ultimately subverted towards the end, however, as the heroes manage to catch up, something that begins to frustrate and enrage Evolt.
- It Amused Me: After he gets back his full power, he decides that he is too amused by humanity to immediately kill them off. Instead, he decides to conquer Japan and let them destroy themselves through war. He also decides to develop the Lost Bottles to create Lost Smashes because he thinks it would be ironic if he managed to turn the other Kamen Riders into them, which is why he lets them live for now. Of course, considering that this all comes from his own mouth and he already has a track record for being a Consummate Liar, whether or not this is just part of yet another one of his larger plans is up in the air. Later, it becomes clear that while he does enjoy what he's doing, it is ultimately just stalling and smokescreen for a plan to become even more powerful.
- Karma Houdini: Despite all the deaths he caused and torment he inflicted on the heroes, Evolt survives the Cross-Z V-Cinema with his life intact and enough power to leave the Earth, an opportunity he immediately decides to take rather than pick another fight with Team Build. He doesn't have the Pandora Box anymore, and doesn't seem to have his world-shattering Black Hole or Fever Flow levels of power anymore either, but otherwise Evolt comes out of the movie with pretty much everything he could have hoped for.
- Karmic Death: Ultimately meets his end at the hands of the person he manipulated for his own ends and psychologically tortured throughout the series along with his son who he abused and manipulated the entire series. To add to the karma, the very weapon he used to cause so much misery, the Pandora's Box, is turned against him via the white panel and used as the instrument of his demise.
- Knight of Cerebus: Once his true nature as Evolt is revealed, the plot goes from 'merely' the fate of Japan to the fate of the entire planet and eventually the entire universe. He also manages to rack up one of the largest, if not the largest, onscreen body counts in the history of the franchise.
- Lack of Empathy: When Yui questions Banjou why he wasn't able to save her students, Evolt (in Banjou's body) just says that he doesn't give a damn about them.
- Last of His Kind: With the demise of the other three in the movie, Evolt is the last of the Blood Tribe. Subverted in the Kamen Rider Cross-Z V-Cinema where Evolt's older brother Killbas comes to Earth sometime after Evolt's downfall. Played straight again after Killbas bites the dust.
- Lesser of Two Evils: Compared to his brother Killbus, believe it or not. Evolt is a sadistic Planet Eater, but he at least has a sense of self-preservation and can be reasoned with on some level, while Killbus is just Ax-Crazy and wants to destroy everything For the Evulz.
- Logical Weakness: The Evol Trigger makes him immensely powerful, but it also acts as his biggest weakness. Damaging it causes it to malfunction, which results in paralyzing Evolt, even in his monster form.
- Luke, I Am Your Father: The alien that infected Ryuga's mother and thus turned him into a Half-Human Hybrid was a piece of Evolt, meaning in essence, Evolt is Ryuga's father. After Ryuga regenerates the DNA needed to transform when Evolt stole it, Evolt outright calls him his 'spawn'.
- Manipulative Bastard: He manages to manipulate pretty much everyone into furthering his goals. For the villains, he takes advantage of their ambition and offers them power in exchange for working with him, and for the heroes, he forces them into situations where they either have to do something that furthers his plans or let innocent people, especially close loved ones, die. The end result is usually Stalk betraying whoever was foolish enough to go along with his plans before moving on to the next Unwitting Pawn, all the while getting closer to killing all life on earth.
- The Man in Front of the Man: Plays along with Night Rogue and later Namba's ambitions, when ultimately he's just acting loyal to them in order to further his own plans.
- Master of Disguise: He can use his steam to alter a person's appearance. His helmet has a built-in voice modulator to distort his own identity further. Once he is complete, he is capable of full shapeshifting.
- Meaningful Name/Names to Run Away from Really Fast:
- "Blood Stalk" is a very fitting name for a hunter like him. It also fits the Evilutionary Biologist traits of Faust, as "foundation bloodstock" is a term referring to animals that are used to create new breeds of their species.
- The reveal of what he really is also makes it meaningful: Evolt is from a race of Planet Looters called the Blood Tribe. Thus planets or species he comes across can be considered stock for the Blood Tribe.
- Evolt is a play on evolution and revolt. Evolt's plan involves tricking the heroes into evolving to higher levels, as well as rapidly transitioning through forms himself, and he ultimately revolts against everyone including the last three members of his own race other than himself. The other meaning for revolt is also apt, as he is irredeemably vile and either horrifies or enrages everyone who knows of him.
- Multilayer Façade: He is revealed to be Soichi, and then revealed to actually be an evil spirit from Mars possessing him.
- Necessary Drawback: In spite of his immense power, he does have at least one drawback: he needs all his DNA in order to make full use of his power. If he decides to split off his DNA for whatever reason, the best he can do is use Evol Cobra form. It is still powerful, but not as insanely powerful as Black Hole form.
- Nice Job Fixing It, Villain!: Part of his plan involved manipulating the amnesiac Takumi Katsuragi into gathering the Fullbottles for him as Build and helping him train up both his own body and Ryuga's to Hazard Level 5 so that they could be viable hosts to use the Evol Driver with. While his plans works, this also leaves the two strong enough to combat him as well as any other foes that threaten the peace of the world.
- Obviously Evil: Evolt makes no attempts in any of his identities to hide the fact that he is a supervillain.
- Offhand Backhand: Does this to a Touto guard during episode 11 which resulted in the man exploding into Ludicrous Gibs.
- Omnicidal Maniac: His aim is to complete the Pandora Tower, rendering the Earth as ruined and lifeless as Mars, after which he will move on and do it all over again somewhere else, with his ultimate goal being to eventually consume everything in the universe except himself.
- One-Winged Angel: Evolt goes through more of these than a Dragonball Z villain. By the end, including Blood Stalk, he has eight forms, each progressively stronger than the last.
- Outside-Genre Foe: Until the reveal, the series had been primarily an After the End story dealing with a Balkanized Japan and trying to stop a Civil War from erupting. Then comes Evolt, an alien invader who sends the plot straight into Cosmic Horror Story territory and whose general character and powers are more in line with a shonen Anime Big Bad than the typical Kamen Rider villain.
- Person of Mass Destruction: Evolt is one of only two villains in Kamen Rider history to be a planet buster level power (the other being N-Daguva-Zeba, who was even with Kuuga's planet busting Super Mode), and has wiped out entire planets by himself. Over the course of the series, we actually see him eat an entire planet with a black hole, as well as Earth's moon.
- Pet the Dog: In an evil sort of way: Blood Stalk is the one to help Gentoku become Kamen Rider Rogue after his torture at Utsumi's hands. He is not at all nice about how he does it, and at one point almost gives up and plans to just have Gentoku put out of his misery.
- Planet Eater: It was initially believed that Evolt was from a race of Planet Looters, but the truth turned out to be far worse. Evolt's primary goal on every planet he visits is to consume its resources and move on to the next at the cost of most of the energy he got to get to the next one. Part of the reason he didn't destroy Earth when he had every chance to was the Black Pandora Panel, which when completed enhances his power enough that not only could he warp to other planets without expending energy at all, he could also consume the entire planet instead of stripping it bare without the need for Pandora's Tower.
- Playing Both Sides: Every side receives some form of aid from Stalk, often right before he betrays them to the next person on his list of employers.
- Poison Is Corrosive: His venom can knock someone out, gradually poison them to death, or instantly liquify their bodies depending on how strong a dose he inflicts. It was originally believed to be a power of the Blood Stark suit, but is eventually revealed to simply be a natural ability of Evolt's he can use in any form.
- Poisonous Person: Evolt is naturally venomous. As it is an extraterrestrial venom, he is the only one who can cure it.
- Power Dyes Your Hair: A side effect for some of those unfortunate to have his DNA. Sento's hair turned completely white when possessed, and in a world where Evolt didn't exist, Ryuga's hair was completely black instead of brown.
- Psychopathic Manchild: Even when he flies into a fit of rage, he can't help but rant like a petulant child.
- Rasputinian Death: It took about 5 episodes and a stage show for the Kamen Riders to finally kill him, and even then he didn't stay gone for good.
- Ret Gone: When he was defeated by Build in the finale, the merger of worlds erases him from at least Earth's history. Whether or not it means he is simply already dead and Pandora's Box destroyed without either coming to Earth or he was completely erased from time isn't clear, but as far as the merged Earth is concerned, Evolt never existed. Subverted HARD! as he managed to reappear into the New World in Build NEW WORLD: Cross-Z
- Satanic Archetype: Aside from Cobra being his primary Fullbottle and first Evolbottle and red being his main color motif, he also fits in terms of role, as a manipulator who offers power to the other villains in exchange for doing his bidding only to screw them over in the end while furthering his own plans to kill everyone by starting The End of the World as We Know It.
- Sealed Evil in a Can: Vernage defeated him and crippled his Evol Driver, leaving him weakened and unable to escape Mars, stranding him on the planet he destroyed for millions of years until the Mars expedition accidentally gave him a way to escape.
- Sense Freak: It turns out that up until Sento nearly killed him in Genius Form he had never properly experienced emotions, describing his previous happiness, pain, anger and shock as "performative mimicry". After Genius Form forced him to drop his transformation and nearly killed him however he's started to feel emotions himself and he describes it as "the most fun I've ever had".
- Slouch of Villainy: Manages to outdo Night Rogue in this regard. His first appearance in episode 4 has him actually lying down on a park bench. In full armor.
- Smug Snake: Pun aside, Evolt is an incredibly accomplished fighter and he knows it. He even catches RabbitTank's Vortex Finish in the palm of his hand, compliments the force of the blow, tosses Sento to the side and then remarks on the kick's Hazard Level without even coming close to losing his cool. The only things that can throw him off his game are Best Matches that he has never seen before, and even those usually only work once. Like most examples of the trope, the cracks in Evolt's master plan begin to form because he believes himself to be smarter than everyone else, and starts toying with his victims when he thinks he's won.
- Smug Super: As Evolt achieves beyond the fourth phase of his powers, he backs it up by knowing that the heroes can't touch him. As Team Build rise and counterattack, it slowly bites him in the rear big time.
- Snakes Are Sinister: A cobra-themed villain who is a part of a terrorist group, who is in reality is an alien invader.
- The Sociopath: Everyone else he manipulates are nothing more but stress toys for him to break.
- Story-Breaker Power: By the time he reaches his ultimate form, Evolt can destroy entire city blocks with the aftershocks of a casual kick and summon giant black holes that consume entire planets. Combined with his ability to instantly warp anywhere he desires in the universe with just a thought, Evolt is effectively one of, if not the most, powerful antagonists in Kamen Rider (his only real contenders are Rosyuo, the Overlord of Darkness, and, according to supporting information, N-Daguva-Zeba). Removing the Macguffin from his chest aside, the only real reason he doesn't just kill everyone immediately is because he finds it more fun to watch them suffer.
- Supervillain Lair: After forming the Pandora Tower, he makes it his base of operations.
- The Fighting Narcissist: It eventually becomes apparent that Evolt has an incredibly high opinion of himself as a 'higher organism'. The biggest symptom of this trope is his Berserk Button: he simply can't tolerate having his ego bruised and will go to extreme, spiteful lengths to make those who have done so suffer.
- Those Were Only Their Scouts: Subverted. Vernage is shocked only one of his species was able to wipe out Mars, implying this trope, but when other members of his species appear, Evolt is shown to be considerably stronger than any of them (as well as being the only one with an Evol Driver) and they're subservient to him making it clear Evolt is an outlier. Only Kamen Rider Blood is comparable to him, and he requires a mismatch of Build Driver related items to achieve a form on par with the one Evolt naturally has. In addition, by present day, only five of the Blood Tribe are even left.
- Player straighter when his older brother shows up, and stronger than him even without an Evol Driver.
- The Starscream: Nearly from the moment he shows up, Stalk takes every available opportunity to stab Night Rogue in the back. Rogue eventually catches wise to this behavior, and by episode 10 plans accordingly, not that it helps. If his goals succeed, they will all be dead anyway.
- The Strategist: Calls himself this for Faust and he is very good at formulating long-term plans.
- Teeth-Clenched Teamwork: He partners up with Banjou in their battle against Killbus. While Evolt is eager to work together, Banjou is (justifiably) distrustful of him.
- Time Abyss: Evolt is at the bare minimum millions of years old and older than life on Earth.
- Too Kinky to Torture: He seems to enjoy the beatings he takes from from both Build and Cross-Z, treating them as demonstrations of their increasing Hazard Levels. Subverted once he receives a beating that actually hinders his plans, which he absolutely despises.
- Training from Hell: The Blood Stalk suit was originally created by Takumi Katsuragi to act as a designated rival to those using his Kamen Rider system so that their need to surpass Stalk's initially superior capabilities would drive them to increase their Hazard Levels. In his own twisted way, the current wielder of the suit is fulfilling the technology's purpose while performing a little terrorism on the side.
- Ultimate Evil: For most of the series, Evolt has no physical form of his own and even once he is complete what he looks like under the armor is hidden. This is despite being one of the most vile and powerful villains in the entire franchise. He only gains an actual face at the end of the series, and unlike most examples more than lives up to it with how powerful and horrifying he is.
- Villain Ball: Evolt could have won if he had just killed the other Kamen Riders as soon as he obtained the Black Pandora Panel, but he chose to keep them alive so he could watch them wallow in despair for longer. This provides an opportunity for Rogue to damage his Evol Trigger, buying Sento and Ryuga time to force the Panel out of him.
- Villainous Breakdown: Sento's actions in episode 36 are the first thing to ever make Stalk legitimately lose his temper when there is no one around for him to be fooling or manipulating by pretending to be upset. He gets his plans back on track in short order, but it's the first time something happens that he was in no way prepared for, and he doesn't take it well.
- A second one in episode 41 after he is defeated by Build Genius Form and is enraged that a "lower lifeform" has prevented his plans from succeeding various times.
- And again in episode 45. This time the heroes manage to deal him a decisive defeat that actually sets back his plan right when he could have won. This, combined with the fact that his moves are now limited by everyone knowing his agenda has him seething with rage.
- He gets an absolutely beautiful one in episode 48 as Ryuga carries him into the void between realities to finish fusing them into a world where the Skywall never existed, fruitlessly pounding his fists against Cross-Z Magma and shouting for him to stop. It continues into the episode after, with Evolt furious beyond measure that he's been foiled by the fake hero that he created. By the end of 49, he's still convinced he can win despite his power literally being hacked down and Sento delivering the trademark Rider Kick to finish him off, yelling there is no way he can lose until he is ultimately vaporized.
- Voluntary Shapeshifting: Upon becoming whole, Evolt can assume any form he chooses.
- Walking Spoiler: His identity as Soichi Isurugi is this, and The Reveal that he is another being altogether possessing Soichi is even more this.
- We Will Meet Again: The events of New World allow him to restore a partial strength monster form. He decides that he is going to leave Earth for a while but will return once he is fully recovered. The nigh inconceivable horror of this casually thrown out statement is slightly mitigated by the fact that Banjo now has access to the most powerful form among the Build riders.
- Weapon of Choice: As opposed to Rogue who prefers to Duel Wield the Transteam Gun and the Steam Blade individually, Stalk prefers to fight with the Combined Steam Rifle.
- Wham Line: "What are you trying to do?!"
- Why Don't You Just Shoot Him?: Early on, he leaves the heroes alive because needs them for his plans to regain his full power. Once he does regain his full power, he decides that instead of just up and destroying Earth, he can instead keep using the heroes for another plan to become even more powerful, being too convinced that the heroes won't be able to stop him. However, the heroes end managing to steadily close the power gap between them and figure out his plans, making them more and more of a nuisance to him until they end up managing to set back his plan right when he pretty much had completely won. It doesn't help that he's so petty that instead of straight-up killing Sento (the current biggest roadblock to his plans), he wants to kill Sento last, so that he watch as everything he loves is destroyed.
- Wild Card: Most of the time, Stalk acts completely on his own initiative even if his actions go at complete odds with the goals of his alleged allies. He isjust charming enough, and his allies are all blinded enough by their ambitions and the tastes of power he offers them, that none of them quite realize what he's doing until it's too late. Given his endgame is "kill literally everyone", it is safe to say he's on no one's side.
- World's Strongest Man: Evolt is, by far, the most powerful character in the main Kamen Rider Build series and of the most powerful Riders in the franchise (amongst the riders his only direct competitors are Man of the Beginning Gaim, Post Series-Kamen Rider Decade, Ultimate Kuuga, Killbus and Cross-Z Evol. He's only unambiguously surpassed by Ohma Zi-O, who combines the powers of all Hesei riders and forms including Evol's). His Black Hole Form is capable of defeating any character in the series and allows him to wipe cities off the face of the planet in moments. Initially only Sento with his Genius Form is capable of matching him but he quickly surpasses him by tapping into the Evol Driver's ability to use emotions for strength, becoming so powerful that Genius and Cross-Z Magma, who by the end of the series are comparative equals AND both stronger than Black Hole was initially, can just about slow him down for a few moments. His transformation after incorporating the Black Pandora Panel into himself is borderline invincible, capable of destroying planets in moments. It took the combined might of the other four Riders to fight him off the first time. The second time they needed to exploit a weakness from his Evol Trigger to keep him still and then send him to a pocket dimension to weaken him and it still took the deaths of two Riders and Ryuga sabotaging him from the inside to allow Sento to best him. Even then he manages to come back from THAT and recover his full power yet again. In the end the only way Evolt leaves is in his own terms. Essentially deciding that he doesn't want to destroy the Earth anymore.
- Would Hurt a Child: Stalk opts to demonstrate his Steam Blade's ability to create Smash on the go by using it on a boy no older than ten. And of course, there is the fact that children are among the humans living on the planet that he intends to destroy for funsies.
- Xanatos Speed Chess: The creation of the Sky Walls was actually not according to Stalk's plan, so he writes many of his schemes on the fly.
- In Episode 34, he pulls a Poison-and-Cure Gambit on the heroes, offering Sento's life in exchange for the Pandora Box and all the remaining Fullbottles. However, this enrages Banjou, who fights so hard that he raises his Hazard Level to 5 which allows Evolt to steal his body, giving him even more than he wanted in the first place.
- In Episode 37, he takes over Sento's body, but it can't complete the Evol Trigger even though it is more powerful. Ryuga has gotten his ability to transform back and is even more powerful than before. However, just as he, Kazumi and Gentoku are about to finish him with a triple Rider Kick, he uses the Evol Trigger to absorb the energy of their attack, allowing him to complete it.
- You Have Outlived Your Usefulness:
- His dealings with Faust, Hokuto, and Namba Industries was all in service of a delicate and lengthy plot to boost Banjou's Hazard Level so he could perform a Fusion Dance with him and regain all the DNA the other half of his being held. That accomplished, he has zero qualms about murdering Banjou otherwise.
- The moment he's complete and they're nothing more than an amusing distraction, Nanba Industries is swiftly and brutally annihilated.
Tropes exclusive to him as Blood Stalk:
- Battle Aura: When unleashing his full power, Stalk begins to emit an aura resembling blood-red flames surrounding his body.
- Chest Insignia: He has a green cobra on his chest.
- Finishing Move: The Transteam Gun gives him several, such as the Steam Break.
- Hell-Bent for Leather: Like Night Rogue, his suit features quite a lot of leather from the waist down.
- Made of Iron: Despite the Transteam Gun allegedly setting its user to a fixed Hazard Level, essentially nothing can seriously hurt Stalk unless it takes him by surprise. Even strikes from the berserk Hazard Trigger-enhanced Build only knock Stalk around without actually causing injury to him. He often uses these beatings to read his opponent's Hazard Level.
- Red and Black and Evil All Over: Wears a blood-red suit covered with black pieces of metal.
- Reverse Grip: While Stalk prefers using the Steam Blade and Transteam Gun in their combined form, when he uses the Steam Blade alone he wields it this way.
- Scarf Of Asskicking: He wears a muffler made from... car mufflers.
- Shout-Out: Like many recurring instances of the Bat/Spider/Cobra trio, he's one to Cobra Man, the first Shocker monster from the original series to be revived.
- Sinister Shades: Decked out with a green visor. Like Night Rogue above, it is a second green king cobra, though the eyes are much more obvious. The cobra's tail comes up on the left, giving Blood Stalk mismatched horns.
- Snakes Are Sinister: The Blood Stalk suit has the power to conjure giant cobras that Stalk can command. They're quite multipurpose, being able to carry people in their stomachs or to attack for Stalk. They're also directly as powerful as he desires them to be, so he can create ones strong enough to battle against the likes of Cross-Z Magma or RabbitRabbit.
- Sword and Gun: Like Night Rogue he uses the Transteam Gun and the Steam Blade in combat.
- Whip It Good: His gauntlets house long prehensile whips.
- Willfully Weak: As Stalk continues to no-sell attacks from forms that it's increasingly ludicrous for him to match on even ground with nothing but the Transteam System, it becomes more and more obvious that he's holding back an enormous amount of power while pretending to just be an ordinary human. It takes the likes of RabbitRabbit and Cross-Z Magma for Stalk to finally stop holding back.
Tropes exclusive to him as Kamen Rider Evol:
- Achilles' Heel: The Black Hole Trigger may give him access to outrageous amounts of power, but if it's hit hard enough to get jammed, Evol ends up paralyzed. This becomes vital in fighting him when his power reaches levels the rest of the cast can't hope to match.
- Animated Armor: A variation. According to the data found about the Evol Driver, Kamen Rider Evol isn't so much a suit as much as his host physically transforming into Evolt.
- Bling of War: Evol's suit is drastically bulkier than every other Rider costume and dripping with gold.
- Clipped-Wing Angel: Terrifyingly, the monstrously powerful Cobra Form is a drastically weakened version of Evolt's true Black Hole form.
- "Do It Yourself" Theme Tune: Evolt provides the voice of his own Driver, complete with a mocking "Ciao!" at the end of his finishers. Justified, since it technically is a part of his Bizarre Alien Biology.
- Evil Counterpart: To both Build and Cross-Z, complete with forms designed to be knockoffs of each of them. Like Build, Evol has a red and blue color motif underneath all the gold, and utilizes Best Matches, but he only matches everything against Rider System. Like Cross-Z, he's the fusion of an alien with a human, but his alien half dominates his human half.
- Evol also has the ability to use stolen data on Sento's equipment to create copies for his own use.
- Evol's forms are unique among Riders since unlike Build's which provide Multiform Balance and specific abilities, Evol's forms are clear power boosts and they way he obtains them are more akin to something out of a shonen battle manga Big Bad's transformations.
- Evil Laugh: His belt performs a psychotic one at the end of his transformations. All of them.
- Finishing Move: Like Build's Vortex Finish, Evol can turn the crank on his belt a second time to perform an Evoltech Finish:
- Cobra Form (Phase 1): Evol forms a star map underneath his foot before absorbing it into his leg and delivering a Rider Kick.
- Dragon Form (Phase 2): Evol coats his hand in dark blue flames before delivering a punch that projects an energy Chinese Dragon upon impact.
- Rabbit Form (Phase 3): Either a punch covered in flames and purple energy that sends the target flying, or a roundhouse kick covered in red and orange energy that generates an energy star map upon impact.
- Black Hole Form (Phase 4): Evol delivers the Black Hole Finish, a powerful flying kick to the enemy, sending them into a black hole which kills them after a period of time.
- Alternatively, Evol can summon a massive black hole in the air, which is capable of consuming entire buildings.
- Since he retains the Transteam Gun, he can use its Steam Attack or Steam Shot.
- Flash Step: Despite the massive bulk of the suit, Evol is so fast that he even leaves afterimages when he moves.
- Four Is Death: His most powerful form, Black Hole, is his Phase 4. It gives him the power to destroy worlds.
- Fusion Dance: In New World Cross-Z, he merges with Banjou to create Cross-ZEvol.
- Multiform Balance:
- Obviously Evil: As if his appearance didn't do a good enough job conveying he's evil, his belt gives an Evil Laugh at the end of his transformation. He is not exactly subtle about the fact he's a supervillain.
- Psychoactive Powers: His first clash with Sento's Genius form reduces the power of his Black Hole phase, but gives Evolt the capacity to experience genuine emotions, allowing him to gradually raise his formerly capped Hazard Levels.
- Sdrawkcab Name: His name Rider name is love spelled backwards (it's even stated as such in his theme song) fitting since he's the antithesis to the rider's beliefs of fighting for LOVE and peace.
- Spell My Name with an "S": Kamen Rider Evol his true name, Evolt, with a letter knocked off. However, this does make his Rider name an inverted "Love", one of the virtues Sento professes to.
- Strong and Skilled: Unlike the previous antagonist Dan Masamune, Evolt is not reliant on the overwhelming power of his transformations and can fight competently against any Rider with any of his weaker forms. While possessing Utsumi, he managed to fight far more effectively as Mad Rogue than Utsumi himself could and was capable of killing Utsumi with his weakest form EvolCobra despite the fact that Utsumi also wielded an Evol Driver. Unlike Masamune, Evol has a properly honed fighting style that compliments his overwhelming power, which enables him to fight and hold the upper hand against Sento in his Genius Form. By contrast, Masamune only held the upper hand as Kamen Rider Cronus due to his ability to stop time and was effortlessly beaten by Emu once he gained access to his Hyper Muteki Form.
- Super Prototype: The Rider System was derived from the wrecked components of his Evol Driver, although Stalk never intended for the offshoots to surpass the original, as he just needed them to condition Banjou to reunite with him.
- Unrealistic Black Hole: Black Hole Form, true to its name, utilizes in creating miniature black holes to trap his opponents. He also uses black holes for his transformation sequence and to teleport from place to place. He also replaces Stalk's poison with the ability to simply disintegrate anything he touches. He can even makes larger ones to destroy structures at will.
Portrayed by Hajime Kanzaki (suit)
- Human Identity: Unknown
- Animal Motif: Hedgehog.
- Light Is Not Good: His upper body is primarily white with blue highlights, but he's nonetheless a Smash.
- Small Role, Big Impact: If it wasn't for him, Sawa would most likely never get a lead on Build's true identity.
- Spikes of Villainy: Well, can't expect round edges on a monster called "Needle".
- Starter Villain: The first Smash we see Build beat to a pulp, with no real effort to boot.
- We Hardly Knew Ye: Only appears in the cold opening just for Kamen Rider Build to defeat him.
- Wolverine Claws: Needle primarily creates spikes from his hands.
Strong Smash/Stag Lost Smash
Portrayed by Hajime Kanzaki (suit)
- Human Identity: Shimizu Kyoichi
- A Glass in the Hand: Strong's entire torso evokes the image of a rock being crushed by a giant hand, with what one could call his face being the middle finger.
- Animal Motif: Gorilla.
- Back for the Dead: Returns after Forty episodes after it was revealed that he was one of Shinobu Katsuragi's students. However, after losing as the Stag Lost Smash, he is killed by Evolt.
- Mighty Glacier: Part of his motif is rock based that gives him insane physical strength and durability, and even a trained fighter like Ryuga couldn't beat him. Kamen Rider Build on the other hand...
- Top-Heavy Guy: Strong Smash is essentially a boulder with legs.
- Super Strength: Can punch a car several feats away from him.
Portrayed by Hajime Kanzaki (suit)
- Human Identity: Kasumi Ogura
- Animal Motif: Dragons, though it's not immediately apparent. The protrusions on her sides resemble dragon horns, her element is often associated with dragons breathing fire, and it's the FullBottle that her essence creates.
- Arm Cannon: Burn's right arm is one, which it uses to utilize its fire powers.
- Dying as Yourself: Kamen Rider Build GorillaMond separates the Smash Essence from Kasumi, and holds it long enough so Ryuga can say goodbye.
- Fighting from the Inside: She ends up shooting herself a couple of times in order to stop herself from hurting Ryuuga. Sento notes that this is not common because most Smash lose their identity.
- Killed Off for Real: Unlike the other two Smash Kamen Rider Build fought against, Kasumi was doomed to die since she is classified by Night Rogue as a "Hazard Level One": A person whose body is too weak to survive a Smash transformation, and will die if the Smash Essence is extracted. Kamen Rider Build does kill her, but it's a Mercy Kill at best.
- Playing with Fire: Has a flamethrower motif and can spew fire.
- Small Role, Big Impact: At #31, Rogue reveals that her transformation and death were all to increase Ryuga's Hazard Level.
Portrayed by Kazuya Okada (suit)
- Human Identities: Reika Kine (I)/Shingo Kuwata (II)
A second one was formed from researcher Shingo Kuwata, and was used to be a distraction against Build so Faust could steal the Pandora's Box. After his essence was removed, he used a unpurified bottle of Nebula Gas to kill himself, but not before telling Build that Takumi Katsuragi is still alive.
Tropes For The Smash:
Tropes For The First Flying Smash:
- Adult Fear: Her Smash form was hunting her own child. Luckily she doesn't remember any of that.
- Androcles' Lion: She repays Ryuuga and Sawa as proxies for Build when they're about to be rebuffed from boarding a boat to Seito because he husband lends said boat to the smuggler.
- Chekhov's Gunman: It turns out that she is a friend of Shinobu Katsuragi, didn't know that he faked his death, and was key for the nascita gang to discover that Shinobu was still alive.
- We Hardly Knew Ye: She is shown as a Smash for very little time before Build defeats her.
Tropes For The Second Flying Smash:
- Cyanide Pill: After his job was completed, Kuwata absorbed a lethal bottle of unpurified Nebula Gas to dissolve himself and ensure he couldn't be questioned.
- Go Look at the Distraction: The whole point for Kuwata fighting Build was to distract him long enough for Faust to enact their plan to steal the Pandora's Box.
Mirage Smash/Square Smash
Portrayed by Kazuya Okada (suit: Mirage), Satoshi Fujita (suit: Square)
- Human Identity: Masahiro Nabeshima
- Anti-Villain: Only does what he does because Faust would've killed his family otherwise.
- Adult Fear: He doesn't remember his family after being turned back into human. After episode 12 however, his memories have started to return to him.
- This gets worse when Nabeshima and his family are targeted by Seito's Guardians in an attempt to force a surrender from Touto in the representative battle. Thankfully, Kazumi was there to wipe out the Guardians and get them to safety.
- Dirty Cop: He was a prison guard who handed over prisoners to Faust for their sick experiments. Later episodes reveal that he didn't become dirty by choice.
- Force and Finesse: Both his Smash forms are this to each other. His first is fast, focuses on illusions to confuse the enemy, and has a pair of swords to deal quick strikes, while his second his strong, focuses on his ability to create destructive blocks to hurt the enemy, and seems to have little strategy that goes beyond hitting them as hard as possible.
- Heart Is an Awesome Power: Squares are usually not what one would associate with combat, being geometrical shapes and all. Turns out that they give him a variety of Combo Platter Powers, from creating destructive cubes from any matter, Thinking Up Portals that are square-shaped, and immense strength.
- I Have Your Wife: The reason he acted as Faust's agent in the first place. They would've killed his family otherwise.
- Laser-Guided Amnesia: Downplayed, since he seems to not remember things in general, but it was mostly towards his family and Faust, and even then, there are still some memories of Faust having similar devices to FullBottles. At the end of Episode 12 however, his memories are coming back, and he immediately calls Sento on some new revelations.
- Make My Monster Grow: Blood Stalk does this to him, mostly for fun.
- Me's a Crowd: One of his abilities as the Mirage Smash.
- Ninja: His dark blue colors, illusion powers, and dual swords give his first Smash form this motif. Fittingly, his essence is used to make the Ninjya Full Bottle.
- Small Role, Big Impact: Nabeshima only appears in a few episodes, often in flashbacks, but his role in Ryuuga's prison experiences is vital to solving Ryuuga's fugitive status. Its also thanks to him that Soichi's secret identity gets exposed.
- Nabeshima's impact is such that he's still getting mentioned and his family is used as a plot point as deep in as Episode 28.
- Super Strength: Switches out his Super Speed as the Mirage Smash for this as the Square Smash.
- You Have Outlived Your Usefulness: Once his usefulness in gathering them test subjects had been depleted, Faust turned him into a test subject.
Portrayed by Hajime Kanzaki (suit)
- Human Identity: Kishida Tatsuya
- Animal Motif: Panda, though, it's extremely subtle, even when compared to the Burn Smash. He's mostly shades of black and white, his face resembles that of an upside-down panda, it's the motif of the FullBottle his essence makes, and he's built extremely bulky, much like real-life adult pandas.
- Joke Character: Faust didn't really care how some out-of-shape musician would make for a poor Smash outside of wanting to taunt Build and gauge the defensive abilities of the Touto Government. He's so pitifully weak that the Guardians almost manage to kill him with their regular weaponry and he presents zero challenge to Sento himself once he gets them alone.
- Keet: He's incredibly energetic and friendly.
- Mistaken Identity: Unfortunately for him, he's right about Sento having Taro Satou's face but he's not. Taro was killed to provide a body double for Takumi Katsuragi, with Blood Stalk swapping out their faces and giving the amnesiac Katsuragi the name "Kiryu Sento."
Portrayed by Hajime Kanzaki (suit)
- Human Identity: Takehiko
- An Ice Person: Exactly What It Says on the Tin.
- Animal Motif: Jellyfish.
- Kids Are Cruel: Subverted. Takehiko might be attacking Build and his classmates, but it was not by choice.
- We Hardly Knew Ye: Doesn't stay in his Smash form for more than 3 minutes in his episode.
Strong Smash Hazard
Portrayed by Hajime Kanzaki (suit)
- Human Identity: Kyoka Katsuragi (I); Unnamed soldier (II)
A second one is formed by one of the nameless soldiers accompanying Night Rogue during episode 15.
Tropes For The Smash:
- A Glass in the Hand: Strong's entire torso evokes the image of a rock being crushed by a giant hand, with what one could call her face being the middle finger.
- Animal Motif: Gorilla.
- Mighty Glacier: Since this is a repaint of the original Strong Smash, it still had this ability. It's even more durable than the original, and even a Full Bottle powered Ryuga wielding the Drill Crusher couldn't scratch it.
- Palette Swap: Strong Smash Hazard is a metallic recolor of the original Strong Smash.
- Top-Heavy Guy: Strong Smash is essentially a boulder with legs. This "Hazard" variant is seemingly the same but made of metal.
Tropes For The First Strong Smash Hazard:
- Outliving One's Offspring: She's still alive while her son is dead. Except he isn't, Sento's her amnesiac faceswapped son.
- We Hardly Knew Ye: Doesn't appear for long as Kamen Rider Build FireHedgehog defeats her and takes the essence.
Tropes For The Second Strong Smash Hazard:
- He Knows Too Much: Essentially why the poor sap of a soldier was converted into a Smash: to cover Night Rogue's identity.
Press Smash Hazard
Portrayed by Hajime Kanzaki (suit)
- Human Identity: Eita Kawai; Unnamed prisoner(II), None (III)
A second was made by the Hokuto Government as their first act of declaring war against Touto.
Tropes For The Smash:
- Animal Motif: Panda.
- Palette Swap: Has a more darker metal recolor along with some blue spots on the body.
Tropes For The First Press Smash Hazard:
- Joke Character: Even more so than the first one. Sento had to transform to take that one on, but this Press Smash lost to a FullBottle enhanced Ryuga offscreen. Even worse, this is the Hazard variant so it should be stronger than the original. Even with the Dragon FullBottle's ability to grant stronger enhancements as it synchronizes with its user, that's embarrassing.
Tropes For The Second Press Smash Hazard:
- Took a Level in Badass: This Press Smash Hazard managed to put Build on the ropes and proved to be more of a challenge for the Kamen Riders to handle, at least initially.
Tropes from the Clone Press Smash Hazard:
- Empty Shell: As one of Nanba's Clone Smash, this one has no personality and no human form.
- Took a Level in Badass: Considerably, even compared to the previous Press Smash Hazard. This one kept all three riders on the ropes until Ryuga gained access to Cross-Z Magma.
Portrayed by Kotaro Kaji(suit)
- Human Identity: Sawa Takigawa
- Animal Motif: Octopus. It has the ability to use a barrage of energy tendrils and tentacles.
- Combat Tentacles: Can create energy tendrils and tentacles for combat.
- Long-Range Fighter: It realizes on its long tendrils to attack its foes but it's not great at close range. Once Cross-Z gets close enough, it is swiftly defeated.
Stretch Smash Hazard
Portrayed by Kyohei Yamaguchi (suit)
- Human Identity: Unknown soldier, None (II)
- Animal Motif: Octopus.
- He Knows Too Much: Essentially why the poor sap of a soldier was converted into a Smash: to cover Night Rogue's identity.
- Laser-Guided Karma: For harming Misora, this poor Smash got the business end of a Million Hit from Cross-Z and a fully charged blast from Build KaizokuRessha's Kaizoku Hasshar.
- Oh, Crap!: His human identity had this reaction when his boss suddenly transformed into Night Rogue.
- It happened a second time as a Smash when he realized that both Kamen Riders are gunning for him for hurting Misora and both of them are pissed.
- Palette Swap: Is a black version of the Stretch Smash.
- Would Hit a Girl: Stretch Smash Hazard had it out for Misora, knocking her out rather quickly. This rewards the Smash both Riders' undivided attention.
Tropes from the Clone Stretch Smash Hazard:
- Empty Shell: As one of Nanba's Clone Smash, this one has no personality and no human form.
- Took a Level in Badass: While the original Stretch Smash Hazard was no slouch, it was unable to handle two riders attacking it at once. This one kept all three riders on the ropes until Ryuga gained access to Cross-Z Magma.
Flying Smash Hazard
Portrayed by Jun Watanabe(suit)
- Human Identity: Unknown prisoner
- Animal Motif: Hawk.
- Cool Hat: It looks like a sun hat crossed with a stealth bomber.
- Degraded Boss: Entire swarms of Clone Flying Smash Hazards appear near then end of the series as Mooks.
- Palette Swap: It's a gun metal grey recolor of the Flying Smash.