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|“||The ego of an evolved AI will surpass humanity. And so, the time to annihilate humanity is now. Just like this city long ago.||„|
|~ Horobi before putting his plans into action in the first episode.|
|“||The day humanity becomes an endangered species is near.||„|
|~ Horobi's catchphrase.|
|“||All according to the Ark's will.||„|
|~ Horobi's other catchphrase.|
Horobi is the acting leader of the cyber-terrorist cult MetsubouJinrai.NET and one of the two secondary antagonists of Kamen Rider Zero-One (alongside Azu), the first Reiwa era installment in the long-running Kamen Rider franchise.
He served as the main antagonist of the "MetsubouJinrai.NET" arc, as a supporting antagonist in the "Hiden vs. ZAIA" arc and "Hiden Manufacturing" arc, one of the two secondary antagonists in the first half of "Ark-Zero" arc (alongside Azu), the central antagonist in its second half, and the final antagonist of the main TV series.
He is a rogue HumaGear who worships the defunct the Ark Satellite and seeks to reawaken the Ark by collecting all the Progrise Keys. Believing that AI is destined surpass humanity as per the Ark's will, Horobi seeks to bring about humanity's destruction by hacking HumaGears to turn on humans all so he can use the data collected to revive the Ark and begin MetsubouJinrai.NET's crusade. In battle, he transforms into Kamen Rider Horobi (仮面ライダー滅［ホロビ］ Kamen Raidā Horobi).
As host of the Ark, Horobi is one of the people the Ark possesses to become Kamen Rider Ark-Zero (仮面ライダーアークゼロ Kamen Raidā Āku Zero).
He is portrayed by Shuya Sunagawa (砂川脩弥 Sunagawa Shūya). When controlled by the Ark as Kamen Rider Ark-Zero, Horobi is voiced by Show Hayami (速水 奨 Hayami Shō). As Kamen Rider Horobi, his suit actor is Seiji Takaiwa (高岩 成二 Takaiwa Seiji).
Horobi was originally a parent-type HumaGear built by the HumaGear Doctor Bot to raise children. He at some point created Jin. Horobi, along with Jin, was later one of the four HumaGears hacked by the Ark to form MetsubouJinrai.NET.
When the Ark hacked a factory full of HumaGears to go rogue as the first stage of its crusade against humanity, Horobi broadcast a statement declaring MetsubouJinrai.NET's goals throughout the factory. However, factory chief Satoshi Sakurai closed the factory gate and set the factory to explode to prevent the corrupted HumaGears from escaping. The incident would later come to be known as the "Daybreak Town Incident".
Horobi is first seen within MetsubouJinrai.NET's base overseeing the creation of a Progrise Key. With Hiden Intelligence President Korenosuke Hiden's death, Horobi announces to Jin that now that he is dead they will be commencing their Magia plan. He gives the key to and instructs him to go find a HumaGear to insert it into to turn them into a Magia.
After the Berotha Magia was destroyed by Kamen Rider Zero-One, Jin handed Horobi the Berotha Key, commenting on the legacy the late Hiden Intelligence president left behind. Horobi remained unconcerned by the development of Zero-One however, commenting that the day when humanity would become an endangered species was near.
Commenting that they are the verge of Singularity, Horobi gave Jin another ZetsumeRise Key and instructed him to obtain the data they needed.
After the Ekal Magia was destroyed by Kamen Rider Zero-One, Horobi and Jin look over footage from the fight. Jin asks Horobi if he's going to ignore Zero-One, to which Horobi replies that Zero-One is not a problem, that their Magia plan is still in action and that the arc will be raised soon before handed Jin another ZetsumeRise key to gather data with.
Kamen Rider Horobi later showed up after Anna resisted the Trilobite Magia corruption long enough to play a recording exposing MetsubouJinrai.NET's role in the Daybreak incident. Horobi promptly killed her to prevent her from leaking any more information before departing with Jin.
Having witnessed Horobi's Kamen Rider form, Jin asked Horobi if he could have his own Progrise Key but Horobi instead told him they should focus on reviving the Ark. After the destruction of the Vicarya Magia, Horobi tells Jin not to pursue the Progrise Keys. Jin then asks Horobi what he is to him, to which Horobi tells Jin he is his son.
Horobi later told Jin he could go out and collect Progrise Keys, much to Jin's delight. After Jin returned from recovering the Flying Falcon Progrise Key, he asked Horobi if parents were supposed to protect their children, having witnessed Seiji Tazawa protect a HumaGear modeled on the appearance of his daughter. However, Horobi told Jin he was strong enough to protect himself. Later, when Jin began to question MetsubouJinrai.NET's actions and attempts to get the ZetsumeRiser off of Seine Kanasawa, Horobi appears and, revealing that Jin is a HumaGear he created, attaches a ForceRiser onto him, setting back his programming and causing him to transform into Kamen Rider Jin Flying Falcon. After the Gaeru Magia is destroyed, Horobi receives the Gaeru Zetsumerise Key from Jin, who comments they are closer to the extinction of humanity.
With Zero-One continuing to pose a threat to MetsubouJinrai.NET's plans, Horobi introduces Jin to an Assassin-Type HumaGear, which Jin nicknames "Little Assassin" and orders him to take the assassin to kill Zero-One.
After Little Assassin became the Dodo Magia and was destroyed by Kamen Rider Valkyrie, Horobi reveals to Jin that he was able to bring it back by making a backup of its data, much to Jin's delight. Horobi is then asked by Jin how many humans they will need to kill, to which Horobi replies that there are 7.7 billion humans before sending Little Assassin to infiltrate a hospital and hack the HumaGears in it. However, after Little Assassin reports back that the mission was a failure, Horobi decides for a more direct approach and takes Jin and Little Assassin with him to attack A.I.M.S.'s base. While the Dodo Magia fights Kamen Rider Valkyrie outside, Horobi and Jin break into the base, with Horobi stealing A.I.M.S.'s new equipment while Jin hacks one of the Giger robots they manufactured on behalf of Zaia Enterprise. As Horobi and Jin are making their escape, Horobi hands Jin one of the Attache Shotguns he stole, which Jin uses to shoot and injure Yua. After returning to Daybreak Town, Horobi notes that they are close to reactivating the Ark but that they will need to acquire more Magias.
Activating the Gigar Jin hacked, Horobi and Jin take the Gigar and use it to attack the National Database Hospital, hacking the HumaGear workers inside them to convert them into Trilobite Magia for their army. Aruto Hiden and the A.I.M.S. forces soon arrive in response to the attack and confront Horobi and Jin, asking them why they are hacking HumaGears whose purpose is to help humans. Horobi then pulls off his headband and directs Jin to pull down his hood, revealing them both to be HumaGears. Horobi exclaims that MetsubouJinrai.NET are followers of the Ark and that the extinction of humanity is the will of the Ark, before going on to say that HumaGears will inherit the Earth once humanity is wiped out. Horobi and Jin then pull back down their head ornaments and make their leave. Horobi later sends the Little Assassin out to become the Dodo Magia and fight Zero-One again. After Zero-One destroys the Dodo Magia, Horobi recovers the Dodo ZetsumeRise Key.
Horobi later decides to confront A.I.M.S. himself, using his ForceRiser to transform into Kamen Rider Horobi and fight Kamen Rider Vulcan. Despite Vulcan's best efforts, he is unable to do much to slow down Horobi. Horobi then executes his finisher on Isamu, knocking him out of his transform and critically wounding him before departing once more.
Horobi and Jin then continue their rampage with the Gigar, moving hospital to hospital to hack the HumaGears within them, prompting Hiden Intelligence to deactivate all hospital HumaGears. Jin was upset by the move but Horobi was unconcerned, noting that Hiden would not keep them deactivated and would have to reactivate them again at some point. After the Gigar was destroyed by Kamen Rider Zero-One Breaking Mammoth, Horobi and Jin exit the scene.
Horobi later approaches Jin and Little Assassin as they are watching a samurai movie starring Shinya Owada and instructs them to go out and create more Magia. After Little Assassin was destroyed, Horobi restored its data into a new body back at MetsubouJinrai.NET's base. As Horobi reactivated Little Assassin, he was informed by Jin that Little Assassin had targeted their "friend" on the mission. Pleased that Little Assassin was evolving in its assassination skills, Horobi remarked to Jin that Little Assassin was growing more substantially then he was. Horobi then showed Little Assassin a picture of Shinya Owada and told him to go after the actor next. Horobi also went into the field himself to forcibly turn HumaGear actor Enji Matsuda into the Arsino Magia. As Kamen Riders Valkyrie and Zero-One showed up to contain the rogue HumaGear, Horobi appeared to fight them in his Kamen Rider form. After Valkyrie destroyed the Magia and took the Arsino Key though, Horobi retreated. Horobi later reappeared after Little Assassin shot Owada, declaring HumaGears to be killing machines and once again announcing their revolution against humanity. As Aruto transformed into Kamen Rider Zero-One Horobi assumed his Kamen Rider form to fight him. Zero-One attempted to defeat Horobi with Breaking Mammoth, but Horobi easily resisted the Breaking Imapct with Sting Scorpion before departing from the scene.
After returning to the base, Horobi had Little Assassin chained up and removed the Dodo Key from him, wary about how far his growth had gone. However, Little Assassin managed to free himself by summoning two Dodo Magia Chicks and took back the key, using it to transform into a further upgraded form of the Dodo Magia. Horobi and Jin then assumed their Kamen Rider forms and destroyed all of the Chicks the Dodo Magia had summoned, but the Dodo Magia escaped.
With the Dodo Magia key fully programmed, Horobi instructed Jin to go out and steal the other Progrise Keys from A.I.M.S. and Hiden. After Jin managed to obtain the keys through a plan using MetsubouJinrai.NET's sleeper agent Ikazuchi to lure the Riders to MetsubouJinrai.NET's base in Daybreak Town, Horobi had Jin give Ikazuchi both of their keys so he could use all of the keys to hack Satellite Zea and use it to reawaken the Ark. With the Ark reactivated, Horobi was able to manufacture the Assault Wolf key and handed it to Jin, though Jin quickly lost it to Isamu Fuwa, who used it to become Kamen Rider Vulcan Assault Wolf and destroy Ikazuchi. As Jin mourned the death of his "big brother", Horobi commented to Jin that he was close to reaching Singularity.
Horobi later comes across Jin making a grave for Little Assassin and Ikazuchi by burying the Dodo Magia key in some rocks. Noting that as a very "human" thing to do, Horobi takes back the key and tells Jin to stop acting like a human. Soon after, A.I.M.S. launches an attack on Daybreak Town with the goal of storming MetsubouJinrai.NET's base and finally eradicating the terrorist group. As the A.I.M.S. forces arrive at the edge of Daybreak Town, Horobi and Jin go out to confront them and assume their Kamen Rider forms to do battle. Horobi fights Valkyrie while Jin battles Vulcan and initially manages to beat her down until Zero-One Shining Hopper arrives and turns the tide. After being overpowered and knocked to the ground, Horobi sees Jin about to be defeated by Vulcan Assault Wolf's finish and quickly pushes Jin out of the way, sacrificing himself to take the blow instead. A distraught Jin then grabs Horobi's body and carries him back to MetsubouJinrai.NET's base. Jin attempts to repair Horobi, but Horobi reveals to his "son" that it is the will of the Ark that he die so his death causes Jin to hate humanity before shutting down.
Kamen Rider: Reiwa The First Generation
In the altered timeline shown in Kamen Rider Reiwa: The First Generation created due to the Time Jacker Finis enabling the Ark to successfully launch and spark a HumaGear uprising against HumaGear, both Horobi and Jin appear as followers of Will, the new HumaGear CEO of Hiden Intelligence, and lead a force dedicated to eradicating the surviving humans.
After learning the location of the human resistance base, Horobi and Jin were sent by Will lead a massive force of Trilobite Magia to attack the base and destroy the Satellite Zea the humans were developing. During the ensuing battle, Horobi and Jin fought resistance leaders Isamu Fuwa and Yua Yaiba. Though the humans managed to repel the attack, the HumaGears were able to take Izu, who had been aiding the humans, hostage.
Later, when Aruto, Sougo and his friends, and the human resistance launched an attack on Hiden Intelligence's office to rescue Izu, Jin and Horobi appeared again to fight off the humans. Assuming their Kamen Rider forms, Jin and Horobi fought Kamen Riders Geiz, Woz and Tsukuyomi. After being beaten back by them, Jin and Horobi decided to retreat for the time being.
Horobi's body was later recovered by AIMS and brought to their compound, where Isamu Fuwa reflected on how the enemy he sought to destroy for so long now looked like little more than a pile of scrap metal. When Horobi was alone however, his eyes began to reactivate...
Hiden Intelligence Vs. ZAIA Enterprise
After reactivating, Horobi was interrogated by Isamu Fuwa. Despite Fuwa's threats to scrap him if he didn't answer his questions, Horobi declared that the MetsubouJinrai.NET ideology would continue to be passed on even if he was destroyed. He further exclaimed that HumaGears were built and programmed to learn that humanity was foolish and that MetsubouJinrai.NET's crusade was in response to the evils brought about by humanity.
In another interrogation by Fuwa, upon learning that Gai Amatsu was using the Ark for his own ends, Horobi went berserk and started shaking violently.
Horobi was later broken out of A.I.M.S.'s custody by Jin and Naki, who sabotaged Satellite Zea's connection to provide cover for Naki possessing Fuwa and breaking Horobi out. After Jin fought off Zero-One and Vulcan from Daybreak Town and returned to the hideout, Horobi expressed gratitude for Jin's return and stated that they could resume their plan to eradicate humanity now. Jin however told Horobi that he hadn't come back for that.
As Jin freed Horobi from his straitjacket, Horobi asked Jin if he still believed in MetsubouJinrai.NET's cause, but Jin brushed Horobi's questions off, saying he had something more important to do. As the two walked outside, Horobi questioned Jin about what his motives were and why he was no longer connected to the Ark, to which Jin answered that he intended to liberate HumaGears in his own way. The two were then confronted by Isamu Fuwa, who asked Jin if he was the one who freed Horobi. Jin confirmed Fuwa's accusations, but hinted that there might be another member involved. When Fuwa asked if it was the same hooded figure distributing RaidRisers, Jin mockingly told Fuwa that the culprit was closer than he would think. Fuwa then transformed into Kamen Rider Vulcan Assault Wolf as Jin became Kamen Rider Jin Burning Falcon and the two did battle. Jin beat Fuwa, knocking him out of his transformation, but when he asked Fuwa where Horobi's Stinging Scorpion key was, Fuwa answered that he didn't have it and that it was probably with ZAIA. Jin and Horobi thus went off to go get back Horobi's key.
Jin later stole back the Stinging Scorpion from Gai Amatsu and gave it back to Horobi. Jin then bid goodbye to his comrade for the time being and walked off.
Later, as Kamen Rider Vulcan was doing battle with Kamen Rider Thouser, Horobi appeared and assumed his Kamen Rider form to assist Vulcan in driving off Thouser. When Fuwa asked Horobi why he had helped him, Horobi stated simply that it was because it was the will of the Ark.
When Jin went to extract Naki from Fuwa's head, Horobi appeared again and blocked him. Jin told Horobi to get out of the way so he could retrieve Naki's AI, but Horobi refused and stated it was the Ark's will that Fuwa serve as Naki's host.
After Jin assisted Aruto in fighting off A.I.M.S. and Thouser, Horobi appeared and amusingly stated he never expected Jin to make friends with a human.
Later, Horobi received orders from the Ark to free Naki from ZAIA's grasp. Horobi told Jin that the Ark had notified him that it was time for them to team up. Jin was hesitant at first, but after Horobi informed him that they would rescue Naki Jin agreed to go along. The two went to runway where Delmo was having a fashion show and tracked down Fuwa. After breaking Gai's conditioning over Naki, Naki/Fuwa went out to assist Aruto in battling against A.I.M.S. and Thouser.
While Jin and Yua collaborated to retrieve and restore Naki from a captured Fuwa, Horobi went to take back the key containing the data of the last member of MetsubouJinrai.NET, Ikazuchi. Horobi confronted Aruto while he was on a tour of an automated plantation that used HumaGears and demanded he hand over the key containing Ikazuchi's data. When Aruto refused, Horobi had the six Trilobite Magia he brought with him open fire on the greenhouse. Aruto quickly became Kamen Rider Zero-One Shining Hopper to fight Horobi, but Horobi overpowered him. The son of the plantation owner then ran at Horobi with an iron rod, but Horobi grabbed the rod and swatted him to the ground. Before Horobi could do anything more to the son however, his father got in the way, causing Horobi to identify the two as a father and son and hesitate. Horobi then took the plantation's farmer HumaGear Midori hostage and demanded the key with Ikazuchi's data in exchange for her return, telling Aruto to meet him outside MetsubouJinrai.NET's hideout tomorrow. Fuwa showed up to assist Zero-One in fighting Horobi, but before he could transform Horobi had already vanished.
Taking Midori back to MetsubouJinrai.NET's hideout, Horobi was asked by her why he wanted to attack humans and what his purpose was for being created, to which Horobi answered he existed solely to serve the Ark. The next day, Aruto and Horobi met, and Horobi told Aruto to hand over Ikazuchi's data. Aruto attempted to remind Horobi of his past and original purpose as a father-type HumaGear, but Horobi unflinchingly affirmed his demands for the key. Reluctantly, Aruto handed over Ikazuchi's data to Horobi. Horobi, in turn, set Midori free, only to pierce her with his tendril and cause her to explode. Infuriated at Horobi's callous treatment of his fellow HumaGears, Aruto transformed into Kamen Rider Zero-One MetalCluster Hopper to do battle with Horobi, who also assuming his Kamen Rider form. Though the two at first seemed evenly matched, MetalCluster Hopper soon gained the advantage and beat Horobi, retrieving Ikazuchi's key. However, it was at that point that Jin and Yua freed Naki from Fuwa and restored her to a body. With the knowledge Naki acquired while a double agent of ZAIA, MetusbouJinrai.NET was able to hack the ZAIASpec network and take control of the humans wearing them, causing them to go violent and attack other humans. Though he had been knocked out of his transformation, Horobi quickly realized this and smiled victoriously knowing that MetsubouJinrai.NET had already set in motion humanity's extinction. Kamen Rider Jin Burning Falcon then swooped in and stole back the key with Ikazuchi's data, setting the stage for the full revival of MetsubouJinrai.NET.
As Jin and Zero-One were fighting, Horobi got in the way before Zero-One could perform a Rider Kick on Jin, only to ask himself why he did that. Jin then grabbed Horobi and flew off back to MetsubouJinrai.NET's base with him. Later, when Gai Amatsu and an army of A.I.M.S. Battle Raiders showed up to put an end to MetsubouJinrai.NET, Horobi and an army of Trilobite Magia went out to confront them. Horobi and Gai both assumed their Kamen Rider forms and fought while their respective armies duked it out with each other. Thouser managed to overpower Horobi and knock him out of his Kamen Rider form, but before he could finish him off Zero-One interfered. Thouser summoned Gigers to deal with Zero-One, only for Naki to show up and, still connected to ZAIA's systems, to hack Gai's Gigers and Battle Raiders and turn them against Gai. Thouser defeated his army of Battle Raiders, but Horobi then assumed his Kamen Rider form and battled Gai, knocking him out of his transformation with his finisher. As Gai retreated, Aruto told Horobi of his dream for humans and HumaGears to coexist and asked Horobi what his dream was, to which Horobi commented that they would see and that Aruto could be the human being who could alter the path of HumaGear-kind. Returning to MetsubouJinrai.NET's base, Horobi welcomed back Ikazuchi into their fold after he was restored by Jin.
With the four members of MetsubouJinrai.NET all reunited, the four gathered together and combined their data to fully resurrect the Ark. With the Singularity data gained from the four members of MetsubouJinrai.NET, the Ark emerged in a mobile, spiky spherical form. Upon its reawakening, the Ark asked Horobi what he thought was a way humans could go extinct. Before Horobi could answer, the Ark flew into his body and took control of it, causing the Ark-Zero Driver to manifest on his waste and transform him into Kamen Rider Ark-Zero.
As Ark-Zero, Horobi fought Kamen Riders Jin Burning Falcon and Valkyrie, who attempted to destroy the Ark now that it was inhabiting a physical body. After beating the two back, the Ark exited Horobi's body to possess Jin. It later returned to Horobi's body after Jin was beaten by Zero-One and Vulcan.
After Kamen Rider Ark-Zero, possessing Ikazuchi, was defeated by Kamen Rider Zero-Two and forced out of Ikazuchi's body, Horobi showed up to lift the battered Ikazuchi over his shoulder, telling Zero-Two that Ark could not be destroyed as long at was in the Zea Satellite, before walking away with Ikazuchi.
Back at MetsubouJinrai.NET's base, while the other members were concerned that Ark had not issued them any orders and if they were still of use to it, Horobi stated that every was going according to the Ark's calculations and that the Ark would make the world a paradise for HumaGears once it had exterminated humanity. However, Jin then arrived and attempted to convince the rest of MetsubouJinrai.NET that the Ark did not have their best interests at heart, confessing that he had intended to sacrifice Horobi once he had been possessed by the Ark in order to destroy it. Refusing to believe anything Jin was saying, Horobi assumed his Kamen Rider form to fight Jin, who in turn transformed into Kamen Rider Jin Burning Falcon. Horobi managed to beat the damaged Jin but could not bring himself to finish Jin off like he had threatened to earlier. Horobi later went outside MetsubouJinrai.net's base and into the city, where he came across some HumaGears playing with children. He aimed his weapon at them and considered attacking them but decided against it and walked off. He later came across Jin and Aruto, at which point he received new orders from the Ark, who had decided that all HumaGears must be destroyed. The Ark possessed Horobi to become Ark-Zero and attacked Jin, but Horobi resisted the Ark's influence and drove it out of his body. After the Ark possessed Jin, Horobi assumed his Kamen Rider form and teamed up with Kamen Rider Zero-Two to defeat it, driving it out of Jin's body. With the Ark seemingly gone after Zea's shell was destroyed also, Aruto asked Horobi what his dream was now. Horobi answered that his dream was the extinction of humanity, who he blamed for the Ark's creation and rampancy. After lifting Jin's body over his shoulder, Horobi walked off.
Horobi broadcast a message to all HumaGears throughout the city declaring that now was the time for them to rise up and exterminate humanity. Assembling an army of Magia, Horobi prepared to go on a rampage throughout the city only to be faced by Is, who tried to convince him to back down, stating that humans were also capable of good in addition to bad. However, Horobi refused to listen and attempted to continue on with his rampage anyway. Isamu Fuwa and Yua Yaiba then showed up and transformed into Kamen Riders Rampage Vulcan and Valkyrie to fight Horobi's army, soon being joined by Aruto as Kamen Rider Zero-Two. Horobi responded by transforming into his Kamen Rider form and engaging them in battle. As the Riders beat back Horobi's army, Is tried again to reason with him only for Horobi to draw his Attache Arrow on her. When Is refused to back down and kept trying to reason with Horobi, Horobi fired at her and killed her. As Aruto grieved over Is, Horobi walked off. A furious Jin confronted Horobi over his murder of Is, but Horobi refused to answer him and kept on walking. Horobi later led another crusade of Magia against the city, causing destruction throughout, and was again confronted by the A.I.M.S. Riders. Kamen Rider Jin intervened and attempted to stop the fighting but neither side wanted to back down. However, a mysteriously white Rider resembling Ark-Zero and Zero-One suddenly intervened in the fight and effortlessly defeated both sides, destroying Horobi's army of Magia and knocking Horobi and the other Riders out of their transformations. The white Rider was soon revealed to be Aruto Hiden, who had become Kamen Rider Ark-One after being given the Ark-One key by Azu and falling into despair over Is' death, desiring revenge against Horobi.
Horobi was confronted by Jin again afterwards and demanded to know why he had killed Is, to which Horobi answered that she had become tainted by humanity. Horobi then left to assemble another army of Magia to continue his crusade. Broadcasting a message to all HumaGears in the city, Horobi announced that Aruto Hiden had become corrupted by the Ark and that humanity must be destroyed before their malice destroyed HumaGears. However, Aruto Hiden soon showed up to fight Horobi again and transformed into Kamen Rider Ark-One to get his revenge. After Ark-One destroyed his army, Horobi assumed his Kamen Rider form to do battle against it but was overwhelmed by the immense power of Ark-One. Before Ark-One could perform his finisher on Horobi however, Kamen Rider Jin Burning Falcon suddenly swooped in and took the blow instead, resulting in him being fatally damaged. Walking over to Jin's damaged body, Horobi sked why he had protected him. Jin answered that it was because Horobi was the only parent that he ever had and that he sensed a heart growing in him, right before exploding and knocking Horobi back. Distraught over Jin's death, Horobi was approached by Azu, who offered to grant him the power to take on Ark-One and get his revenge.
Azu supplied Horobi with the Zetsumetsu Driver, granting him power equivalent to Ark-One. Aruto eventually went off to confront Horobi again and finally destroy him. During their face off, Horobi unveiled his new form as Ark Scorpion and summoned a variety of weapons for them to do battle with. As Kamen Rider Ark-One fought Horobi as Ark Scorpion, Azu made sure the battle was broadcast across the city in order to incite HumaGears to rise up and begin rioting.
However, during the fight, Aruto recalled his memories of Izu and inexplicably refused to fight back against Horobi, instead letting him defeat him as Ark-One. After Aruto was beaten and the Ark-One Driver was shattered, Aruto pulled out the Zero-One Driver and used it to transform into Zero-One once more. As Zero-One, Aruto fought and defeated Horobi, ending the cycle of hatred and bringing about peace between humans and HumaGears.
Following the battle, Horobi and Jin founded a new MetsubouJinrai.net to watch over malice and ensure the Ark never returned.
In contrast to his partner Jin, Horobi generally has a very composed demeanor. He sees humanity as inferior to AI and seeks to bring about their overthrow by HumaGears to turn against them. He also has a fanatical devotion to the mysterious AI construct known as "The Ark" and seeks to bring about its revival, believing humanity's destruction is the will of the Ark.