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Aritomi Haruki (有冨春樹 Aritomi Haruki?) is an anime-original character introduced in the Toaru Kagaku no Railgun S anime series. A bespectacled student of an unspecified institution in Academy City, he is the leader of STUDY, a group that desires to show their power in their esper-obsessed city and is the primary antagonist of the Silent Party Arc.


He is a tall and slender bespectacled male wearing his black hair short. He wears round-framed glasses, and is often seen wearing a lab coat over his uniform of sorts, which consists of a buttoned-up collared shirt and pants, both blue-green in color. Aritomi Haruki's physique seems appropriate to his interests — slim and lacking any muscle — that may suggest a lack of exposure to strenuous physical activity.


Cold and analytical, Haruki has shown to have some sort of detestation towards esper abilities to the point where he will try to demonstrate the bad effects of excessive reliance to esper abilities to the public if given a chance. He is also quite an eloquent speaker, capable of convincing a random crowd of his opinions.[1] Like his comrades in STUDY, he has little regard for life other than their own, and is willing to put into harm innocent civilians just so he can have his way.[2] However, he often makes his next move through majority vote among the members of STUDY.

His mannerism, which he shares with most of the members of STUDY, involves adjusting one's glasses with his finger.


With only a few people present, Haruki gives a speech to his peers in award ceremony in the Academy City Research Exhibition Assembly.

Aritomi is a student, a genius even by Academy City's standards.[3] Every year he participated in the Academy City Research Exhibition Assembly, and at least for two years straight, have won the top awards for his research. Despite this, he saw that the recognition of his genius and the efforts he has put through paled in comparison to the espers, of which the city pours all its attention to. None has yet come against that unfair system, where he thought, that despite how much effort one puts into their studies, how many papers one publishes, only espers are ever recognized by the city.

One day, Aritomi thought about the uncertainty of the nature of esper power development, which is largely determined at birth, and how the production of high-level espers are based purely on chance. This uncertainty was something that Aritomi decides to eliminate by making an esper from scratch (i.e. making an artificial human being that possesses esper abilities). A new method of producing espers based on a completely different approach, a more reliable method to produce espers of a uniform quality, and as many as anyone could ever want, thus begins the Chemicaloid Project.[2]

Haruki joins up with several like minds to come with the plan, and presented it to underground organizations to gain their support. However, they did not see its worth, and among them, Kihara Gensei, whose Level 6 Shift Project would have become a competitor against their project, even called their plans a mere "summer school project."[2] Dismayed by this, they determined to do the project on their own.

Aritomi and his colleagues soon established the STUDY Corporation, and with their technology supplied Anti-Skill of their tools,[4] and manufactured drugs and other chemicals of a wide spectrum.[3] Most likely, these are fronts to fund their project. Moreover, Haruki himself quit school.[3] Their company later buys an old factory for an insane price for their project.[3] Their actions and plans however are not unknown to the darkness, as exemplified by Therestina Kihara Lifeline, who is aware of their Chemicaloid Project and how they want to exhibit.[3]

The first two products of their experiment later bore fruit. Janie, the core of their plan, and Febrie, the spare, used the research of Nunotaba Shinobu as their "base program" to ensure that their automatic nervous functions keeps them alive.[2] However, they made it so that their bodies produce a chemical that would kill them if not for a special lollipop whose ingredients are a closely guarded secret by Aritomi himself.[5]


Silent Party Arc

Main article: Silent Party Arc

Word of Haruki's decision to opt out of the Academic Assembly has reached the scientific community. During this time, STUDY has already begun preparing for the Silent Party that they believe shall shake the foundations of Academy City's esper program.[4] Among their actions over the past few weeks involved buying Shinobu from ITEM[4], gathering data from the rank-fourth Level 5 Mugino Shizuri,[1] and mass-producing Powered Suits to be used to bring the Assembly into chaos legally, covering up their trail by using jammers to disrupt the operation of security cameras and other electronic devices.[2] These incidents of "power outages" were a recurrent problem addressed by Judgment 177 Branch Office during the past few days.[1]

During the period of information gathering by STUDY, however, something unexpected happens when Febrie escapes (through the machinations of Shinobu),[2] and the warehouse where the experiment is being held goes into flames. Despite this, Haruki is confident that it will sort itself out soon.[1]

Haruki taking the time of day to shame Kongou through his arguments.

Haruki later witnesses Kongou Mitsuko apprehend a purse snatcher by using her powers. In his response to the incident, he admonishes Kongou for using her powers in public, making an appeal to probability fallacy to support his claims, convincing the bystanders who were previously impressed by Mitsuko and discrediting her act of heroism. Wannai Kinuho and Awatsuki Maaya shortly arrive after finishing their errand of summoning Anti-Skill to collect the snatcher, but Haruki quickly leaves before they can make a case against him. Upon his return to the headquarters of STUDY, he states that all preparations have now been completed, and that it is now time to show the city that is obsessed with espers their power. He asks to make a vote if they wish to proceed to the next step, and all of their members raise their hands in agreement.[1]

Mitsuko and company espies Haruki.

Kosako Shunichi temporarily becomes the leader of STUDY as Haruki steps out of the headquarters, showing up in one of the venues of the Academy Assembly to personally double-check one of his deliveries sent to the venue and to look for their target Febrie. Although he has located Febrie, Haruki was unable to eliminate her using security robots under his control. However, the involvement of the rank-third Level 5 Misaka Mikoto in Febrie's rescue has sparked Haruki's interest in having her as a test subject, which STUDY unanimously agrees to.[6] Unknown to Haruki, Kongou Mitsuko and her friends were able to overhear his conversation about "reclaiming Febrie".

Haruki with Shunichi after their Powered Suit got deactivated.

Haruki and Shunichi later had a Powered Suit kept in an old warehouse while they try and lure Mikoto and her friends (Febrie included) into an ambush by manipulating the routes she was taking and interfering with cellphone signals to stop them from making any calls. During this time, they monitor the events while inside a black van, watching as Mikoto battles the Powered Suit (which was later discovered as unmanned and lacking electrical parts by Anti-Skill). They later made their escape when Kongou Mitsuko unexpectedly appears and defeats the Powered Suit they had prepared. Despite the interruption of their short experiment, Haruki was able to conclude that their experimentation on Mugino Shizuri may also work on Mikoto as well.[7]

STUDY's influence over Anti-Skill affairs become even more apparent, as it was able to prevent Anti-Skill from meddling in their affairs. Meanwhile, with the Assembly soon coming, they discuss their priorities on Janie. Haruki asks if the preparations are going well, to which Sekimura Hirotada replies that it is and turns to Nunotaba Shinobu for confirmation, to which she says that she will do what she can.[5] During this time, he is already suspicious of Shinobu's intentions as member of STUDY, so he lures her into hacking one of STUDY's spare laboratories for the ingredients needed for the neutralizing agent used in Febrie's lollipops.

Haruki with the info regarding Febrie's lollipops.

Soon enough, Haruki himself discovers Shinobu conspiring with Mikoto to save Febrie, handing out the data he had prepared for her in a console room. Here, he reveals that the data now in Mikoto's hands is a dummy, a part of his additional safety measures to keep vital information from leaking out. Now that Haruki has discovered that Shinobu is a traitor, he forces her to make a painful decision — to help detain Mikoto so that she can guarantee the safety of the recipe for the neutralizing agent she needs to keep Febrie alive. Although Shinobu is hesitant to do it, Mikoto tells her to push on for Febri's sake. Shinobu stabs Mikoto with the injector as she requested, despite having the strength and numbers to overpower Haruki, and thus Mikoto instantly collapses due to the effects of the drug. However, much to the shock of the two girls, Haruki destroys the precious data in front of them.[3]

With Mikoto no longer a threat to Haruki, he decides to talk to Shinobu and Mikoto about his actions. Haruki clarifies that Febrie's well-being is not important as she was just a spare for the greatest invention of STUDY Corporation, which they call "Janie".[3] Haruki also relates to Mikoto his life story, recalling his achievements in the Academic Assembly and his frustrations as a scientist whose efforts are dwarfed by those of the espers of Academy City, both of which motivated him to initiate the Chemicaloid Project.[4]

Eventually, Mikoto succumbs to the drug injected into her by Shinobu and passes out. Haruki later has her and Shinobu transferred to an office space somewhere nearby, but was later alarmed when Misaka Mikoto was rescued. He later comes with Sekimura Hirotada and Kosaka Shunichi to the office space where Shinobu is being held, and puts handcuffs at her. Haruki later brings Shinobu to their main headquarters, where she would be forced to assist in initiating the Silent Party the day after.[4]

One last vote on the appointed day.

The following day, at the day of the Academy City Research Exhibition Assembly, STUDY initiates the Silent Party plan, which involves a four-way offensive against the Academy City from the venue that would host the Academic Research Exhibition Assembly, only to be welcomed by many members of Judgment, gathered by the combined efforts of Misaka Mikoto and her friends from Judgment. To counter this defense, Haruki strengthens Janie's power output and confronts Judgment from all four venues using thousands of Powered Suits, which was quickly contested by Judgment's organized hit-and-run tactics. Meanwhile, Janie's link with Febrie while she is using her ability Diffusion Ghost allows Mikoto and Febri to track down Janie's whereabouts into the main headquarters of STUDY. Despite summoning hundreds of his Powered Suits and three of his prototype "Meltdowner machines", Mikoto was able to sneak into STUDY's main console room amidst the chaos Mugino Shizuri was creating out of rage after being deceived and used as a test subject by STUDY.[2]

Meanwhile, Haruki quickly changed plans upon seeing Mikoto's display of might. As he jams the signals of all electronic devices at the four Academic Assemly venues, he deploys larger mechanical units, piloted by two of Haruki's associates, to take care of the Judgment forces. However, the tables are turned back to the side of Judgment when a much larger unit that dwarfs those of STUDY, Kongou Airlines' Ekaterina II S, arrives on the scene, which was later used to subdue Haruki's associates.[2]

Haruki is soon confronted by Mikoto and Febrie as they reach his main console room. With his plans in the Academic Assembly falling apart, Haruki decides to resort to drastic measures, shutting down Janie's link with the many Powered Suits outside to turn Janie into an unstable entity and then ending his life. But, Mikoto was able to stop Haruki from committing suicide, although Haruki later admits that his "last resort" was irreversible. Haruki's colleague, Sakurai Jun, explains to her that they are in a grave situation, as Haruki's last resort involves releasing thousands of filaments from a missile fired 35,000 kilometers above the Earth, and the rampaging Diffusion Ghost will cause widespread AIM diffusion field interference that will affect each and every esper in Academy City.[2]

Mikoto and her friends later stop the AIM bomb from reaching its intended destination, thus ending the Silent Party and rescuing Febrie and Janie from their uncertain lives. Presumably, they are later taken into custody.[2]

Character Art Designs



  • Aritomi's first name literally means "springtime tree" while his surname means "having an abundance (of something)".
  • He shares the same voice actor with Daigo.


  • (To STUDY, from episode 18): "All preparations are complete. Now it's time to show this esper-power-obsessed city our own power!"
  • (To his peers in an awards ceremony, from episode 23): "The idealist says, everyone is born equal.We are all of equal worth. The sportsman screams, no effort goes unrewarded. Work hard for your dreams! It's about how you play the game."
  • (To STUDY, ibid): "Let's get this Silent Party started, then."



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Aritomi Haruki-profile.jpg Kosako Shunichi-profile.jpg SakuraiJun profile.jpg
Aritomi Haruki Kosako Shunichi Sakurai Jun
Sekimura Hirotada-profile.jpg Madarame Kenji-profile.jpg Nunotaba shinobu.png
Sekimura Hirotada Madarame Kenji Nunotaba Shinobu