Kumokawa Seria

Kumokawa Seria (雲川 芹亜) is a side character in the Toaru Majutsu no Index series. She is a third-year student attending A Certain High School and is described as a genius. She's currently employed by Kaizumi Tsugutoshi, one of the twelve members of Academy City's Board of Directors, as his advisor, and leader of his "Use of Force Unit".

Appearance
She is called a “beauty senpai” by her kouhai students as a tribute to her attractive looks, which feature shoulder-length black hair, fringe tied back, and a fine body with an exceedingly ample bosom.

She commonly wears a school-issued sailor uniform with its standard skirt changed for a “defensive” long one. Her navel is readily observable in the gap between her blouse and skirt. She is smart and athletic, and looks so accordingly.

She supposedly needn't worry about money, only needing red tea to go along with cake. Although an adolescent, she could taste the difference between brandy's; she even wouldn't look out of place should she drive around in a sports car. Of course, the latter descriptions were just an impression others would get when they look at all.

Personality
She is considered to be a very manipulative and calculating person who thinks of the big picture many times; however, she is not above abusing this intelligence for her amusement in regards for rather peculiar sense of humor, especially when it comes to pranking Touma. One time she gave Touma a notebook, where he was tricked to think it would teach him actual hypnotism, where the instructions included having the hypnotized girl lift up her skirt. Shokuhou Misaki, the test subject of Touma’s first failed hypnotism attempt, noted on how the notebook had instructions that was obviously in many obscene direction. The last direction, which involved undoing the hypnotism, required the removal of the girl’s panties where Misaki then hit Touma upon hearing the direction; considering her intelligence, Seria had likely knew the outcome, beforehand, had Touma actually succeeded in getting a volunteer.

Often than not, people whom she works with feel she is a force to be reckoned with. At other times she can be seen as aloof or arrogant in her manners (something which got Fukiyose Seiri very angry). She seems to enjoy teasing people at times, as Kamijou Touma experienced himself, and once saying that Seiri copied her looks.

While she can be ruthless, she is a good person and tries her best to stop the tragedies she knows about, like when she had the gemstones rescued, and regrets when she couldn't stop them, like when she thought Touma died in World War III. Seria has also shown to have a deep emotional attachment to Kamijou Touma, especially when she had heard about his supposed death; during that time, Seria was noted to had became lethargic and regretful to know that neither she, nor the director Tsugutoshi, could help out Touma despite the fact they had power. This is further shown as Misaki, while Seria initially kept a wary guard from the sudden visit of Mental Out, had asked for help in regards to her confused memories related to Touma thus made Seria decided to drop all suspicions and decided to assist Misaki. Humorously, she later admitted her romantic feelings about Touma as Misaki questioned Seria if, in regards to her confused memories, this was all a ploy to keep Touma all for herself; while Seria did deny the accusation, she audibly pondered on Misaki's unintended suggestion as the idea had never occurred to her and it was indeed a drastic action that Seria could have done.

Background
It is unknown when and how Seria became a "brain" for a director but in a conversation with Director Tsugutoshi, she apparently chose to be an upperclassmen with a school life meaning she had a different form of occupation. In Tsuchimikado Motoharu's conversation with Yakumi Hisako, he states that Tsugutoshi has "tamed" her.

She's very knowledgeable in things happening on the Science side, knowing about Deep Blood, Imagine Breaker, and the Level 6 Shift Project. Personally she's very interested in Touma and his ability Imagine Breaker. She likewise respects Touma for all the tragedies he managed to stop, while being depressed that she couldn't do anything despite knowing about them and having a position of power. As she is an important person in Academy City, she moves from stronghold to stronghold for security, and even innocuous apartments she use are filled with traps.

Despite not showing any visible powers, it is most likely she had gone through the Power Curriculum Program due to the fact that she goes to A Certain High School. It’s been implied by Tsugutoshi that she may have been quite close to Touma before his memory loss or at least compared to their current situation. Her time with him has been described as being similar to Shokuhou Misaki, which suggest that she may have similar feelings for him. However, neither of them know about incidents despite being aware about the other's connection. According to Seria, the time she spent with Touma is the same amount of time Misaki did with him prior to his memory loss. In fact her first encounter with him was a result of investigating rumors of a boy wandering a certain area and causing trouble, only to find him knocked out cold after trying to fend of the Skill Outs sent to abduct Mitsuari Ayu, which would be followed up with the two working together to interfere with further attempts targeting Mitsuari. Prior to the incident with Deadlock, in which Touma loses the possibility of ever remembering Misaki due to his brain damage, Seria discovers Misaki being acquaintances with Touma. After he asks to learn about hypnotism from Seria, in her jealousy with Misaki gave Touma a notebook where every direction would be obscene, knowing that Touma will try to follow them on Misaki.

The Second Friday of July
Kumokawa Seria is in her school's cafeteria, sleeping on chairs put together. After being reprimanded by a teacher without anyone around, she communicates using a handheld terminal to communicate with Kaizumi Tsugutoshi, while still lying on the chairs. Starting their "dangerous" talk, Seria references the commotion outside regarding the Gemstones, to which he confirms. Though the director wonders aloud at where Seria gets her information, she dismisses the comment saying that he should be thankful that his "brain" is that excellent. Tsugutoshi then asks her what are her thoughts about the whole situation, to which Seria says that they should leave it be as the people on the outside really can't do anything. Tsugutoshi is skeptical at this plan to which Seria sighs, and says that if a member of the board of directors like him were to write that report, he could simply suppress complaints of the report around him. Tsugutoshi complains however that bureaucracy isn't that easy, though she says that as bureaucratic positions go his is pretty important.

Seria however acquiesces to Tsugutoshi's request as she begins eating in the cafeteria. Seria then mentions the list of Gemstones, and states that since it has been created a little late then United States of America and Russia have noticed that Academy City is making it, ending up with them making the list of Gemstones on their own. She then warns that they might get in the way of their work. Tsugutoshi says that if she knew that then she shouldn't have suggested "leaving it be" just then. Seria tries to confirm if their problems are finding a way to eliminate the problem presented by Gemstones scattered around the world, and other organizations gathering and analyzing Gemstones and creating their own Esper development program, to which Tsugutoshi does. Seria says that it isn't a problem that America and Russia are on the move, and mocks their failure in the Cold War, and assuredly says to Tsugutoshi that the two great powers will be unable to complete their research regardless of the amount of samples they gather as they don't even know what the data means. Tsugutoshi asks how she can be so sure. Seria gives Russia's research as an example, where they have a person activate their special power by fervently praying to Mary. Here, Seria tells him that the Russians can't distinguish between what is "miraculous" or what is not, and that they don't even know what kind of miraculous thing they are searching for. Basically saying that since the Americans and Russian don't even know what path they are going, they can never catch up to them. Still adamant to accept it, Tsugutoshi demands proof from Seria, to which she says that he has to prepare the proof himself. Seria references that despite the claims of a number of institutions developing esper powers, Gemstones, their supposed "sample", are rare. Essentially telling him that it is unlikely for anyone to gather up the few Gemstones scattered around the world.

Tsugutoshi is still hesitant however, to which Seria says that it is the only option and says that he should bear with the extra paperwork as she is his "brain". After a short silence Tsugutoshi then asks what a Gemstone truly is, to which Seria points out that only someone influenced by Academy City would ask a question like that as he always assumed that espers can only be created in Academy City. Tsugutoshi uses the "diamonds" metaphor here, referring to Gemstones as having been created when the exact same circumstances found in the laboratory are recreated in the natural world. He cites the Gemstones of Academy City, Deep Blood and Imagine Breaker, but says that they don't seem like proper powers. He explains it as if their powers lie in a different direction than the straightforward powers in Academy City. Seria adds the 7th-ranked Level 5 esper to his list, and explains to him that Gemstones having strange powers is a characteristic of theirs. She says that though they aren't powerful and are just rare, that alone gives them value to Academy City. Finally, Seria advises Tsugutoshi one more time as his brain, saying that he shouldn't categorize the Imagine Breaker as a Gemstone. She says that she doesn't know the details but she says that its wielder is much more interesting than they think. Remaining silent for a bit as he was surprised that Seria said that she "didn't know" something, Tsugutoshi says that Seria seems to be enjoying herself. Here, Seria replies that she does because thinking is part of her job.

After school, Seria sees Kamijou Touma having the misfortune of having the sprinkler malfunction and having it spray water on him. Seria just laughs at him and says that the most meaningless things always happen to him, to which Touma tells her to shut up and says that is just his usual misfortune. Seria replies, saying that if Touma looks into how his misfortune works then he might be able to find an interesting set of rules behind it. Touma then says that Seria seems to be enjoying herself, to which she confirms, saying that she is and because of things like Touma's misfortune that she loves life so much. With a giggle, she concludes that the school is overflowing with exciting things.

The Second Friday of October
Kaizumi Tsugutoshi invites Kumokawa Seria into his fancy home for a conference with a CIA agent on his home theater system. After complaining of his expensive taste, the conference starts with the CIA agent explaining to them that the recent spate of simultaneous targeting of Gemstones all over the world has nothing to do with the CIA. The CIA agent explains that even though the CIA started the Stargate Project in the past to create their own espers for military purposes, but says the recent incidents have nothing to do with them. He then advises them to look over the organizations that are involved and then they will see that he is telling the truth.

Seria says that he is telling the truth, saying that the various academic organizations, scientific thought groups, sports engineering groups, and human trafficking organization that are involved seem to be uninvolved with the CIA and doubts that they are backing them. The CIA agent agrees, saying that just because they are well known doesn't mean they are behind every world conspiracy.

However, Seria points out to the man that for all those organizations targeting Gemstones, there are two CIA spies, surprising the man. She tells him that they noticed the CIA creating a network of their own with the organizations without the organizations even known. She asks him why, saying she doubts the leader of their country approves of their method. The man starts talking, but Seria simply ends the connection.

With that Kaizumi asks what she thinks. Once again, as Seria has stated before, even if they gather and tinker with the Gemstones they will just fail and that they can leave them alone. For the Stargate Project, she says that it is obtaining the information on the failures of those individual organizations courtesy of its spies there, saying that failures are the seeds of success. She says that if they refer to the data on countless failures to create an outline, they may be able to succeed. Tsugutoshi asks what the odds of them succeeding, to which Seria says 0% and that they need not worry.

Seria explains that even if they fail, they won't know how to use all the data they gathered, putting them in a standstill. Regardless, as long as they don't know that they have failed they will continue to use up the Gemstones. Tsugutoshi is relieved but asks her what they should do now. Seria says to him that he is still naive. He tells that though the organizations will fail on their own, he doesn't like what they are doing to the Gemstones. He then stops referring to them as Gemstones and says that they are kids that happen to have a certain ability. Seria says she has already answered that question. She says that it with only around Gemstones in the world it would be faster to take care of the Gemstones themselves. She advises him to invite them to Academy City as it would be the most efficient method of protecting them from the various organizations. She tells him that his kindness forestalled him as despite thinking the Gemstones as kid who have lives of their own but in the end he did nothing. Tsugutoshi admits he was at fault as well, but now says that she is asking from him something impossible. Tsugutoshi says that the organizations are using the Gemstone list that CIA prepared via different routes than theirs to begin "mining" the children nearby. He tells her that if they dispatch forces they still won't make it in time to stop the "mining" taking place simultaneously across the world.

Seria responds that thought it is true that they won't make it in time even with the help of the supersonic passenger planes, they still have cooperative institutions scattered around the world working with Academy City. Tsugutoshi reasons that the institutions are merely companies and that fewer than 10 of them have military capabilities, as such they would be unfit to lead the rescue of the children. Seria says that it may be true on the surface, but they still have a trick up their sleeve with them. She says that she doesn't like owing favors, but they should bow down to the Frog-faced Doctor for help. Tsugutoshi asks what she is talking about, to which Seria explains that she is going to have to rely on girls with identical faces to fight for them.

Thus begins Academy City's operation to rescue Gemstones of the world.

Later, after the operations were successful, she later hires Kinuhata Saiai to assassinate George Kingdom, the mastermind behind the "mining". Just before Saiai arrives, she makes contact with George through his secret radio frequency. Here, she asks him if he has done sorting everything out, saying that it is underhanded to not even give him a trial after making an enemy out of an entire country, Academy City, subtly implying to him that he will be murdered. Hearing this, the dumbfounded George can only mumble her given name. He then asks her if mass-produced the girls that attacked the facilities around the world, to which Seria confirms. She says that because cloning humans is illegal in international law and the girls taking military action was an unnecessary risk then she owes some for it and that she should at least take care of the aftermath.

DRAGON Arc
Seria is briefly mentioned by Tsuchimikado Motoharu when GROUP is on the run and in needing an ally on the Board of Directors to fight against Shiokishi. Here Motoharu rules out Tsugutoshi as an option, since Seria would not be fooled easily and might advise him against helping GROUP.

Homecoming Arc
She meets Touma again when he returns to the city but heavily intoxicated, she is one of the group of girls that follow him back to his dorm only to later leave. It is revealed that during his absence from the city she became lethargic and commented on being regretful neither she nor the director Tsugutoshi could help out Touma despite the fact they had power.

After an attempt to re-energize herself, she commented she couldn't keep such appearance even for a conversation as it was hollow and she was not like Shokuhou Misaki to which Tsugutoshi replies she must if she ever wants to resume her connection with Touma implying they knew each other more than it seems at first.

Eve of the Festival
Kumokawa Seria is greeted by her sister, Maria, after she inexplicably comes out during the festival preparations. Seria comments on how it's only because people won't shut up being her turn. Maria thinks this as a veiled insult, and asks if she is talking about the beauty contests being held at various schools for the Ichihanaransai, and curses Seria if her "assets" have grown. Seria notes on how she will not be entering, and that her role is only behind the scenes, as such, she doesn't like standing out too much. Moreover, she states that Shokuhou Misaki will just manipulate the votes using her powers, rendering her entering useless.

Maria then accuses Seria of trying to say that she doesn't stand out a lot, to which Seria just says that it is just a difference in chest size. Maria says that Seria shouldn't become arrogant regarding that, and stop looking down on her. The two then argue about the values between large breasts and flat chests. However, much to Maria's consternation, Seria begins talking about Kihara Kagun, that she deems that Maria loves so much that it gives her nosebleeds, and involves his name in their little breast talk. The talk then transfer to what Maria was doing in Baggage City. Here, she asks if Maria really did fell in love with Kamijou Touma, and states that she will go "full-on soap opera mode." Maria then answers that it is a defamation of her character, and asks where she heard that rumor.

During the Festival
Seria reappears to have change her mind about the swimsuit competition in Eiri High School, though she claims that she doesn't even know how she found herself in the stage in the first place. There, she maintains a distance away from Shokuhou who comments on why she isn't coming near the stage with her, calling her an old woman, to which Seria states that it is used to get out of the range of Shoukuhou's powers.

Agitate Halation Arc
Kumokawa Seria is with Kaizumi Tsugutoshi in School District 3, during the height of Motoharu's quest for vengeance against those who have "killed" his sister, Tsuchimikado Maika. Here, it is shown that they too have been investigating the Agitate Halation Project and the killing of Maika. Seria warns of Motoharu's impending advance towards them after being contacted by him that he is coming and he is serious. Although he predicted that he would come for them, he asks Seria what to do next. Seria states that no matter what they do, Motoharu will always go after them, as such, the only way to deal with him is to confront him head on, telling Tsugutoshi to remove all the normal guards, removing his hiding places.

Seeing him as a threat to their plans to stop Yakumi Hisako's Agitate Halation Project, the both of them is determined to stop Motoharu and his clichéd rampage of revenge. Seria says that they need someone to intercept him, and says that she will make preparations in which breaking in the front door is the only route available for him. She then suggests that she herself will suffice, and will use a method that Motoharu will hate the most. Although Motoharu is cautious of the fact that it seems they are luring him in, he predictably enters the only route Seria has given him. There, she confronts him in the entrance hall and says how she thought he would choose this route, the two schoolmates. Motoharu mocks her ineptness as he can simply shoot her from his position and she has no cover. But Seria reiterates her point and blankly states that she has total control over him. Motoharu asks if the Agitate Halation Project is important enough to warrant the "death" of his sister, to which Seria states that she has no obligation to answer him. Motoharu reminds her that he has the Wildcard coccus, but Seria states that Motoharu had no intention of releasing the bacteria in the first place as he didn't have the guts, as is the reason why she isn't wearing a mask and protective suit. Seria notes on how he didn't just scatter it beforehand and even had to contact them saying that he does so as proof of her knowledge, and she was right. Kumokawa Seria has profiled Motoharu before he arrived. Seria points out that Motoharu likes to thinks himself different from other people in the Dark Side of Academy City, a sense of professionalism that would not allow himself to involve people who are not part of the dark side, as such he will not use W. coccus. Hearing this, Motoharu asks her if he can read his pain, to which Seria says that it is cliched. Motoharu agrees, but warns her that she doesn't everything about him and that even if her data on him is accurate it is still faulty. Seria points out that what he's thinking is because she led him to thinking it. And with that, there is nothing left to discuss between them.

Wanting to quickly eliminate her, Motoharu makes the first move and takes out a fully automatic handgun. He shoots at her, but it did not hit her. Despite his marksmanship, and the fact that Seria did not do any special tricks, none of the bullets hit her as she descends the staircase. She keeps on smiling and asks if he thought that a full automatic weapon would make his "heart" disappear. She tells him that no matter what weapon he wields, so long as it is wielded by human hands, the human hear will bleed through, allowing for it to create an opening that she can take advantage of. Motoharu, annoyed takes a handgun that was rigged to become an explosive. With a range of three meters, the handgun explodes, but Seria remains unscathed, and once again mocks Motoharu. He shoots his handgun on her, trying not to let her advance, but it does not good against her.

Kumokawa Seria has analyzed and read every move Tsuchimikado Motoharu has made as well as used her surroundings to influence his decisions. Using her mind, she took control of their "hearts" and made use of their fear to make them lose their true potential. Seria decides to walk leisurely according to rationalizations. Motoharu approached right in front of her, abandoning his weapons and opted for hand to hand combat. However, Motoharu was an open book, and she could read all of his moves, claiming that his status has dropped to the same level as an average high school girl. Suddenly, Motoharu's hand reached out and plucked out her eyeballs. However, despite this, Seria simply mocks at his attempts. With a smile, she revealed a hidden handgun inside her sleeve and shot at Motoharu's gut, making him collapse. Seria points out his flaw, she states that he was the type to slowly savor his revenge, but when he started to eliminate her as quickly as possible, he should have realized that he was being led on by her. With the deed done, Seria tries to call Tsugutoshi on how it is over, and to prepare the parts she had put in Micro Cosmos as a replacement for her missing eye.

Just then however, she felt a strange pressure in her chest. She soon discovers that Motoharu is still alive and that he is using her eyeball for a spell. It is magic, something Seria has no knowledge about on Motoharu, the only missing part in her profile on him. Using her eye as a medium, Motoharu was able to put a curse on Seria and she collapses, a battle won out of simple lack of information.

Seria comes to after Motoharu has left to get to Tsugutoshi. Exhausted, Seria could only move her fingers, she took her phone and used an anonymous address to contact someone who could stop Motoharu. Influenced by Agitate Halation, using all her might she sent a message to someone whom she deemed to be a hero that could stop Motoharu, Kamijou Touma. Before Touma arrives, Seria later withdraws from the building. Much later, her missing eye is replaced.

After the events of the arc, and having her eye successfully replaced, Seria is sent to execute Motoharu for his actions. There on a bridge, he greets asking if her eye is okay, to which she states that it has been eight hours, as such she doesn't feel strange in the eye anymore. With that done, Seria asks him if he is ready, and he confirms it. She takes a large handgun and fires paint rounds on him containing his blood. The force knocked him out into the river. And though, he is still alive, convincing the dark side is all it takes that would allow him not to be attacked again by them as they already have given the sign that they were convinced. It was the etiquette in the dark side of Academy City. Seria then contacts Tsugutoshi to confirm the "kill", he asks if she will recover the body, but states that someone else will pick it up for them, as because the both of them knowing each other may cause strange conspiracy theories if she did, like the execution was an act and that he is still alive. Hearing this, Tsugutoshi states that it would be best to let their enemies pick him up. With that, she ends her call. Her punishment of Motoharu for taking her eye is done, and her sparing of his life by her was because it was thanks for not telling Touma about her.

Shifting and Fluctuating World
In the second recreation of the world by Othinus, known as the Version_Beta world in-text, where another "Kamijou Touma" exists living Touma's life. Both Seria and Maria are first seen walking home together. Ever they busybody, Maria complains about Seiri moving again, but the latter mentions that it is not something to be worried about, much to Maria's chagrin. As they argue about Seria's inherent laziness, Seria mentions that she is relieved that Maria's obsession with working only applies to her, and that she was worried that Maria might live in some guy's house, casually mentioning "Touma" of course. As they argue of who really likes "Touma", he and Index come upon them as they ride a bike. After much arguing, Index slams the breaks and catapults "Touma" out of the bike. This eventually leads to "Touma" falling between Maria's legs, much to both Seria and Index's chagrin. Maria tries to explain to Seria on how she is fine with it because she wears panties for her abilities. As "Touma" is in danger of being bitten by Index, he gives Maria a piggyback ride, his head between her thighs in order to stay Index biting him, knowing that she only bites him. Maria naturally cries out as he does so, and gathered strength in her thighs to keep her balance, annoying her sister Seria. "Touma" tells to Index to calm down or else he won't put Maria down while they shop, though Maria as well doesn't want to be piggybacked either while they're shopping. Index agrees with him, stating that she will have to master some techniques using her arms and legs, much to "Touma's" horror. Seria then mentions on how Maria is grinning a little bit, and casting aside her cool and intellectual demeanor, screams and dropkicks on "Touma's" back. He falls, but Maria manages to land safely. He later ends up in Index's skirt, to which she tells him to prepare himself for some pain. Both Maria and Seria attack him as well afterwards.

In the final recreation of the world by Othinus created specifically to break Touma's spirit, known as the Version_Omega world in-text, where several characters from the original world have been "saved" or have not experienced great tragedy, the now-broken Touma partakes his "last meal" as he decides on the method on how he should kill himself, he sees Seria again, but this time with Misaki. As they usually are, the two of them are arguing after Misaki uses her power to cut in line with elementary students just for a hot-dog.

VS the World
Seria later contacts the Hikoboshi II to inquire to Amano Kaguya on what she is going to do after Academy City decided Kamijou Touma and Othinus should be killed. Here she is teased for being Touma's "ally" and discovers that Kaguya was tasked with firing a cargo at Touma and Othinus' location using the S5.

Mental Out Arc
Prior to the start of the arc, Seria apparently finds Motoharu again and offers him a peaceful school life in exchange for using him. At some point, she apparently has Motoharu act as a chair.

Discovering that her memories with Touma may have been tampered with, Misaki visits the only known person who can rival her with when it comes to manipulating the mind, and has a connection with Touma in the past, Seria. After breaking into her apartment alone through the balcony after using her powers to determine that her front door is rigged with a trap, Seria calls Misaki on her cellphone, asking why she dropped in all of a sudden, wondering if all Tokiwadai girls are the same. Misaki points out that Seria might be guilty of something as she quickly escaped, though Seria points out that she did so because she didn't want to be near hear and her powers. Misaki asks how she knew she was coming, to which Seria says that she scattered cameras around the area to make a personal security network, noting Misaki's weakness with machines. Seria then orders Motoharu to act as a sniper against Misaki, surprising her as she didn't find any information regarding this with her powers, though Seria points out that she can be fooled when she temporarily overwrites her own memories and going around touching everything. After Seria reveals how she got her sniper in the first place, as well as the fact that the entrance is rigged with a trap, Misaki discovers that Seria is willing to talk as she hasn't killed her yet. When Seria hears that Misaki wants to know about her role with her and Touma, Seria becomes silent, and offers to meet in person, having no choice now that Touma's name has been mentioned. Misaki discovers that Seria was just behind her. She warns Misaki that she has ordered her sniper to shoot immediately if she starts acting oddly, saying that making her a hostage won't do her any good.

Misaki tells Seria that she is unsure if her memories of Touma are accurate, but says that if she has some evidence with someone who interacted from back then, then it may be helpful for her. Seria points out that the time she spent with Touma is the same and that they were only acquaintances. Seria notes that the two of them do not know each other's circumstances in their time with Touma, preventing Misaki from comparing her memories with her. Misaki then shows Seria the whistle Touma gave to her prior to his memory loss, to which Seria notes is a fairly common item in School District 7. This makes Misaki conclude that the only other person they know that they could ask is Touma, which is out of the question as they know he lost his memories. Seria then suggest to the disappointed Misaki that technology may have something to do with what happened to her. Misaki says that she thought it was Seria's doing as she believes that she could have Touma all to herself, though notes that it would only make sense if she was still in contact with Touma. Though this just surprised Seria as she could've done what Misaki said so herself. Back on topic, Seria states that whoever pulled the technology on Misaki may have something to gain from her manipulating her memories. Seria says that the technology used is likely very specialized for her in order to fool her, and that she might be able to find where it came from. Knowing that Misaki's weakness is technology, she has her come with her to the bathroom, and with that ending Seria's sniper (Motoharu) targeting Misaki.

Seria asks Misaki to strip down to her underwear in order to check for traces of the technology implanted on her, much to Misaki's embarrassment though she acquiesces to the request. After searching around her body, Seria finds something in back of Misaki's neck, and pulled it out of Misaki's body, much to the latter's shock. Seria orders Misaki to put her clothes back on as she analyzes the device using a computer. Using her power as a Board of Director's brain Seria is able to determine that the device known as a Strobila that affects the organs that secrete hormones, which can affect the brain. Seria says that the Strobila she pulled ran all the way to Misaki's heart. Seeing this, Seria says that it proves that it wasn't really her that messed with her memories. Misaki replies that it is Seria's fault for always sneaking around in the background, saying that even Touma called her a mysterious and creepy old woman who wore too much wake up and had disgusting lumps of fat, which shocks Seria and says that Misaki must be just making it up. After recovering, Seria tells Misaki that if Misaki can look into the people connected to the research institution that developed the Strobila or anyone who could have stolen the data then she can reach the culprit behind it. Misaki says that she should probably thank Seria for what she has done but then asks when the Strobila was attached to her. Seria states that since she had Stroible or a derivative device attached to her, she shouldn't trust her memories and actions too much. This pains Misaki, knowing that her memories with Touma may not be real. Seria asks what she will do now, warning that the culprit may target her again, and says that it is up to her if she will continue on or turn back. Misaki agrees with Seria, saying that she will decide what to from there on. Misaki later leaves.

Misaki later contacts Seria again where she tells him that the Ground Geo from her memories, the place where she met Touma again, should still look the same according to the official records and says that the documents she had gathered have their "last modified" dates altered. Misaki says that if the people behind the changes can change the dates then they can't be certain about what she says "actually" happened as well, saying that it is possible someone in the past added in the data with the time set to the future. Misaki adds that altering the data isn't the same as altering the truth as they might've overwritten the accurate data with identical accurate data, as such she would assume the data is false when she found evidence of their changes. Seria notes that classification rank of the files is rank S, noting that whoever is behind it is someone who has clearly broken away from their loyalty to the Board of Directors, and says that she cannot tell if it is real or a bluff. Seria says that the culprit has the power and conviction to do something on this scale, and that is just a step in their preparation, telling Misaki to be careful as Touma isn't strong enough to handle someone's death. Seria then says that if she does die, then she will give her the proper decorations so she should make sure to contact her. With that their conversation ends.

Despite this, Seria later makes contact with Touma, telling him that it is a girl's birthday (likely referring to Mitsuari Ayu and her suicide attempt prior to Touma's memory loss) on that day Misaki confronts Mitsuari, and that he should set flowers for her on the Ground Geo. Wanting to know what Seria meant, Touma goes to where Misaki and Mitsuari are to find out and discovers their battle, helping to resolve the conflict that happened there in the name of the memories that they had for him that summer a year ago.

Magic God Invasion Arc
During the Anti-Crime Orientation Seria is assigned the role of a "hostage", but spends her time instead in a room in A Certain High school she uses as a "secret base". She later saves Touma from Misaka Mikoto's Railgun, when he climbs up from the floor below through the windows, mistaking him for a pervert as he was wearing "criminal" clothes for the roleplay.

As they hide from Mikoto, Touma discusses his distaste for the Acrobike, as well as Seria trying to put up airs around Touma. When it becomes clear that the students that are roleplaying as the "police" (specifically Fukiyose Seiri, who was chasing Touma earlier), Seria suggests that he should just leave the school as the orientation isn't limited to their school. Touma leaves for the lockers, but much to his confusion. Likely wanting to help Touma more to escape the school, she is later irritated by Touma's obliviousness as he tells Seria that he will use the Acrobikes that Komoe ordered for them.

Both Seria and Mikoto are present when Touma finds a "love letter" in his locker, which is secretly from the Magic God High Priest trying to lure Touma to the rooftop. Much to their horror, Touma is actually ecstatic that he has received a love letter. Seria tries to steer Touma's excitement away from the letter by pointing that there should be a girl he likes, all the while describing that girl to be her. Touma turns her argument down, believing that a girl confessing their love is better. Both Seria and Mikoto then vow to kill him for this. As Touma leaves for the rooftop, Seria wonders why anyone would sign a letter with their school's name.

Christmas Eve Arc
During the events on Christmas Eve surrounding the resistance to Operation Handcuffs, Accelerator's plan to eliminate the Dark Side of Academy City as the new Board Chairman, Seria considered the circumstances behind Neoka Norito and R&C Occultics, having to write up a report on the pros and cons of intervening or not intervening in the situation.

Operation Handcuffs Arc
During the events of Operation Handcuffs on Christmas Day, the Kumokawa sisters swiped Gekota and Bunny Grey costumes as disguises in order to blend in and survive the night in School District 6.

New Year's Eve Arc
On December 31st, she brought Touma with her to Shibuya, as she wanted to investigate something in the Miyashita Ark and Touma sought a part-time job for survival money, with the group subsequently being involved in the events caused by Aradia and the Bologna Succubus over him.

New Year's Arc
Kumokawa returned to Academy City with Touma's group early on January 1st, but wandered off on her own after Touma had said he wouldn't be making his New Year's shrine visit right away. The GPS tracker she had slipped onto the Bologna Succubus was not used in the end as Alice Anotherbible and the Bridge Builders Cabal came to Academy City themselves first.

Daihasei Festival Arc
A small part of her body is shown wearing A Certain High School's PE uniform during the three-legged race in which Misaka Mikoto and Kongou Mitsuko competes in. She is a commentator along with the Pirate Radio DJ found in Toaru Jihanki no Fanfare. Here, she refers to herself as "Bare navel headband."

Toaru Majutsu no Index: Love Letter Competition
Seria is the main character of a short story found in the artbook rainbow spectrum:colors by Haimura Kiyotaka, in this story she set ups a plan on where she will catch a spy by using a love letter from her to Kamijou Touma, under the logic that the spy will believe the love letter to be an actual important confidential message from Seria to Touma; for this purpose Seria creates a great ruckus and makes it quite known that she wrote a letter to Touma. At the end of the story not only Kumokawa catches the spy, but it is also slightly hinted that she is aware of Touma's memory loss.

Abilities
Seria has no special powers, but has a very high intellect instead. She is shown to be an extreme planner, in that she orchestrated a plan to catch the spy by using a "love-letter" to deliver to Kamijou Touma, so as to create a ruckus and let the spy think she is delivering secret documents.

She is also said to be an expert in manipulating people's 'hearts', using only words or hypnotic suggestions, making her enemies fear her and create a mistake if they panic. This, combined with her intellect also allows her to predict people's actions. Even against an expert assassin with weapons like Tsuchimikado Motoharu, she was able to control most of the battle until he used Magic, which is outside her knowledge. Seria is also able to apply self suggestion on herself to dilute pain, but she comments that it isn't perfect. Shokuhou Misaki has even openly acknowledges that Seria skills at manipulating people can match her Level 5 ability Mental Out, which is the strongest mental power in Academy City.

Later on, it is shown that she's physically adept to perform a dropkick with enough strength to send Touma flying while at the same time catching Maria that fell from the air.

Design Evolution
Seria's design remains static throughout the series. Haimura strayed from making look moe, as she has an extreme facial expression that is difficult to convert into a standard moe format.

Quotes

 * (To Kamijou Touma, from SS2): "This school is overflowing with exciting things.”"
 * (To Kaizumi Tsugutoshi, from NT 1): "Kumokawa Seria, the Super JK Tactician bossed around by the Board of Directors, is here!! I’ll dull the judgment of any pure boy☆!"
 * (To Fukiyose Seiri, from Love Letter Competition): "Oh, well, let's ask someone else. Hm, who should I look for...? Maybe that person with black hair, a huge forehead, and large breasts, the one imitating me?"
 * (To Kumokawa Maria, from NT 5): “By the way, I have a serious question for you. Is it true you fell in love with Kamijou Touma in Eastern Europe? If so, it’s time for full-on soap opera mode.”
 * (To Tsuchimikado Motoharu, from NT 7): "Are you aware you are only thinking that because I led you to think it?"
 * (To Tsuchimikado Motoharu, ibid): "Did you think your ‘heart’ would disappear if you used an explosive?"
 * (To Shokuhou Misaki about Kamijou Touma, from NT11): “I don’t really care about you or anything, but he isn’t strong enough to handle someone’s death. So don’t go off and die. If you do die, I’ll give you the proper decorations, so make sure you contact me.”

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Seria Kumokawa