Arisu Sakayanagi

Appearance
Arisu is a petite teenage girl with lilac colored hair and violet eyes. She wears the standard female school uniform, with her accessories being a black beret on her head with a gray ribbon connected to it and a white pair of stockings with garterbelts.

She often walks with a cane and is quite short for her age when comparing to other classmates, due to her. Many people in the school finds her cute but are afraid to approach her due to the power and dominion she wields.

Personality
Arisu appears to possess a "go with the flow" attitude as she accepts most situations without protest or complaints. Although she does openly voice her dislike of boring situations after Kōhei Katsuragi (Arisu's classmate) spoke about the class scores. Unlike Katsuragi, who has a conservative stance, Arisu possesses an innovative outlook on things. Together, the pair effectively lead Class A through the school years. In the eyes of her schoolmates, she is considered to be someone who stands out from the rest and that no one has ever seen her lose her composure. In truth, she is just like any normal girl and the only one who is allowed and seen her act that way is Kiyotaka Ayanokōji.

She enjoys situations she finds interesting as shown when she smiled at Kakeru Ryūen's declaration to rule the school or when she listened to the speech of Suzune Horikita.

In the light novels, Arisu enjoys toying with people, as seen when she cryptically hinted that she knew Kiyotaka, whereas he doesn't remember meeting her before. Later on, while being together with Honami Ichinose, she also appeared to be very confident and complacent after Teruhiko Yukimura of Ayanokōji Group boldly claimed that D-Class has a plan to overtake A-Class soon. She always carries an aura of imperturbability and seems like a wiseacre whenever anyone is in her presence. Although her soft tone could effortlessly make people feel comfortable around her.

Additionally, although she has an easygoing personality, it was shown in the latter part of the series that she is easily provoked when being described based on her petite appearance (e.g. "Little Girl"), as she believes that it does not give her justice, due to her domineering qualities. She may come off as egotistical and arrogant towards onlookers, however this is also a frequent use of one of her tactics to establish control over the minds of those she chosen. She also holds grudges but doesn’t exhibit them on the outside.

Background
Since her childhood, Arisu always believed that a person's potential is simply tied to their genetic, and that a child with superior DNA will always be on the top. After visiting the White Room with her father, Chairman Sakayanagi, she found that one certain child in the facility was outsmarting everyone else in chess, overwhelmingly defeating his opponents, one after the next. Among the children, he was the only one snatching away Arisu's gaze and heart. According to her father, his name was Kiyotaka Ayanokōji, the son of the person running the facility. Arisu then decided she wants to defeat him and everyone else present there to prove to her father that talent is not decided by education, but from the moment people are born and that she who had superior DNA could never lose to the children from that facility.

Plot
Arisu is introduced in the anime when she and Kōhei Katsuragi were being talked to by the Student Council President about the school system.

After a while, she is seen next to Kōhei Katsuragi in the hallway while observing the class points for each class. She then proceeded by commenting on how things gets very boring due to seemingly no struggle between the groups.

One day, while out in the rain she and her followers met Kakeru Ryūen and his followers. While her group protectively surrounds her, she stops them. Ryūen then remarked on how it looked like that she had established her rule in the school very quickly and only in a manner of weeks. He swore to her that he will take down all the classes including hers at the end so that he would be the one to rule the school. She simply smiled at his declaration, sardonically remarking of how he was going to make things fun and interesting for her, before agreeing with his previous statement of her accomplishment.

Volume 5
In the light novel, Arisu made her debut in Volume 5. Due to her health condition, she was unable to partake in the Sports Festival.

After Kiyotaka Ayanokōji's remarkable performance in the final event in the Sports Festival, Arisu asks Masumi Kamuro to bring Kiyotaka to the 3rd floor of the special building, where there is no surveillance camera installed. After Kiyotaka arrives, Masumi leaves the place and Arisu meets him. Arisu mentions the relay race and confirms she was the one calling him to come. She then reveals that she has known him for 8 years and 243 days, which Kiyotaka says that it was not possible since he doesn't recall meeting her.

As Kiyotaka is about to leave, Arisu mentions the White Room, to his surprise. She is also aware that he was the one pulling the strings behind D-Class's previous exam result. Kiyotaka tries to stay composed and denies his involvement, stating that there were a few strategists in his class that were capable of that feat. Arisu then states she has no intention of exposing him, claiming she's the only one worthy of burying the false genius and that she has found some ample enjoyment now that he is there.

Kiyotaka then earnestly asks her if she could really bury him. Arisu laughs at his statement says that she has already begun to enjoy their interactions. She announces that she will fulfill her life's desire by destroying the greatest masterpiece his father has made.



In her short story, Arisu was reminiscing about the sports festival, more specifically dreaming of Kiyotaka, and his race against Manabu Horikita, the Student Council President. She revealed that from her point of view, Kiyotaka was way faster than Manabu during that race (the only reason Kiyotaka lost the race was that one of the other participants incidentally tripped and fell to Kiyotaka's lane, causing Kiyotaka to lose the race by changing his track). After her monologue, she awakens and says that she 'wants him' while also wondering why he came to the school in the first place and questioned his reasons for being in D-Class, claiming it doesn't bother her if she ends up being his enemy one day. She began to enter into a long discussion with Katsuragi, about their competition with B-Class. She then mentioned how she initially thought Ryūen was going to be the main person to make things interesting for her, until she was reunited with Kiyotaka. Arisu then asks Masumi to watch Kiyotaka closely and reflects on how much he has grown since the last time she saw him and that she will enjoy seeing what happens next.

Volume 6
During the Paper Shuffle special exam, A-Class decided to target and attack B-Class. This decision was Arisu's and not Katsuragi's since he would have chosen the much easier option which was attacking D-Class. This showed the main decision-maker within A-Class with Arisu's faction holding the upper hand.

A-Class won in their confrontation against B-Class and was awarded 100 class points.

Volume 7
Later in the series, Arisu became acquainted with Honami Ichinose. As they walked together, they briefly met Ayanokōji Group and talked about how D-Class is fairing well with the recent test, The Paper Shuffle, which massively damaged C-Class' standing. Arisu stated that during the same test, the score difference between A-Class and B-Class is reasonably insignificant, thus concluding that both classes must have the same average intellectual abilities. Honami teasingly stated that if her class doesn't have their guards up, surely, D-Class will surely take their throne. Teruhiko Yukimura made a snarky remark that not only Honami's class will be targeted, but also eventually Arisu's as well. After his bold statement, an awkward situation sparked among all those present driving Arisu to laugh lightly to help ease the situation. Honami observed the Ayanokōji Group members' body language — that they might be feeling too uncomfortable with the two leaders being present, so they bid goodbye to the group.

Afterward, Arisu is seen interfering with Ryūen's interrogation of Rokusuke Kōenji. Following a long argument between the two leaders, the dialogue ended with them discussing the identity of "X". Just before Rokusuke is about to voice his thoughts, Arisu immediately stated that there is a possibility that "X" doesn't exist and that Suzune Horikita should be at the watch-list given that she's the one who manipulated the settings during the special summer exam at the deserted island.

The scene proceeded with Arisu being saved by Masayoshi Hashimoto after Ryūen violently assailed her for repeating Rokusuke's embarrassing nickname for him (e.g. "Dragon Boy"). After this, Rokusuke made a degrading nickname for Arisu (e.g. "Little Girl") which provoked her into proving that his naming sense doesn't give justice to the name-holder. The scene ended with Rokusuke stating that his thinking is beyond the realm of normal common sense and that no one is allowed to interpose with whatever he wants to say if not to face his wrath.

In the short story, Arisu calls Ryūen telling him that she wants to meet with him in person at the vending machine outside the dormitory. When arriving later, 10 minutes late, Ryūen notices that Arisu's faction, Kitō, Hashimoto and Kamuro, are also there waiting for him, being Arisu's bodyguards. Arisu mentions Ryūen's visible injuries, having suffered from his defeat at the hands of Kiyotaka Ayanokōji on the rooftop, which sparks some provocations between both sides. Arisu then says that she wants to ask Ryūen about his fall from being C-Class' leader. Arisu wants to know wheather it was because of Kiyotaka. Ryūen asks if Arisu would ever acknowledge a defeat, being a prideful person. Arisu replies that she cannot possibly lose to someone, and a life without pride would be boring, to which Ryūen argues it is pointless to have a life of showing off one's pride. Arisu then tells the reason she wants to meet him directly like this, stating that it is hard to believe Ryūen, being a tyrant, would lose to his subordinate and fell from his leader position. Ryūen declares he has no further intention of doing anything else in the school, causing a reaction from Hashimoto. Arisu talks about his contract with Katsuragi being a pathway for Ryūen, while also warns that there is no guarantee it will continue to go well for him, in case he loses a large amounts of points. She then reassures that her focus of attack is now on B-Class, to which Ryūen has no objection. Ryūen decides to leave, his last words to Arisu being a reminder that she is not a winner whose victory is guaranteed, which she acknowledges. Ryūen reaffirms he has no intention of being involved in classes dispute, but believes he will crush Arisu if she were to individually challenge him.

Volume 7.5
During the winter holidays, Arisu runs into Kiyotaka and they decide to converse. She reveals to him that she has already heard about Ryūen stepping down as leader. Arisu asks Kiyotaka if he was the one who defeated Ryūen, to which he denies that he had any involvement in that situation and she doesn't press any further. Instead, she says that she felt left out due to D-Class and C-Class having their own battles and that she wanted to find an opponent for her own to play with, having decided on Honami Ichinose. Arisu tells him that she plans to attack her at the start of the next term and that if Honami were to disappear, she might have no choice but to find other targets to destroy. Kiyotaka adds some provocation by saying he wonders if Arisu is good enough to destroy Honami since she perhaps got into A-Class because her father was the director of the school. Arisu doesn't appreciate his words. As they were talking, Masumi comes looking for Arisu telling her not to disappear from their arranged meeting place like that. With Masumi there, they started talking about whether Honami really is a good person, and she reveals a little about Honami's secret to Kiyotaka. Masumi says that the secret Honami keeps is the same as the one Arisu uses to control her. Kiyotaka asks Masumi why Honami would tell her something like that to which she said Honami told her about it herself. She also said she obtained the information via cold reading. With her warning given, Arisu and Masumi go off to hang out together.

Volume 8
Arisu is participating in the Mixed Training Camp and while nothing much happens among the first years, an incident where Haruki Yamauchi bumps into her causing her to fall down setting up the stage for her future plans and igniting a personal vendetta within herself. Yamauchi who was not the most sensitive person offends Arisu with his insensitive attitude and remarks. Kiyotaka who watched the scene unfold noticed the situation and her change in demeanor, thus apologizing on his behalf by telling her Yamauchi didn't mean it. Arisu says she understands that but her face showed a much darker emotion. Before they parted ways, Arisu once again asks for Kiyotaka's thoughts of whether he thinks B-Class can wholeheartedly trust Honami as their bank to which Kiyotaka replies that it should be up to B-Class to decide and not their business to speculate.

Volume 9
After the mixed training camp, as the winter term begins, Arisu begins her attack on Honami and her class. She starts by spreading rumors about her through A-Class students before spreading them towards the entire school. The rumors being spread on Honami are that she has 'a history of violence', 'engaged in compensated dating', 'engaged in theft and robbery' and 'a history of drug abuse'. Honami deals with these rumors by simply ignoring them, which Arisu expected to happen. Arisu's plan was for some students to questions if there were potential truths being spread among the rumors, and that if Honami were to complain to the school, her past would have to be revealed as a result, shattering her perfect girl image. After a few days, it appears as though there was no truth to the rumors as Honami successfully ignores them. However, Arisu continues her attack by using post boxes of the students with a letter revealing that Honami is indeed a 'criminal' in the past. This attack seems to have a successful mental effect on Honami who becomes a shut-in after seeing the letters. On the day she sent the letter, she also sent Masumi to go and tell Kiyotaka about what Honami's secret is. With Honami's absence, more students began to speculate that the rumors may be legitimate.

To make good use of her time, Arisu went to launch another attack she had already pre-planned. One day, she visited the C-Class classroom looking for Yamauchi, under the motive of 'hoping to talk to him'. They went to go talk outside the classroom where to onlookers, she appears to be fiddling her hair like a girl trying to appeal to the guy she 'likes'. As there are actually multiple students watching them, she teasingly asks if they could go somewhere more private, playing him into her hands.

On the day that Honami finally returns to school, Arisu takes her faction with her to visit the B-Class classroom to continue her attack, revealing Honami's past to B-Class herself saying that she was a thief and that her class should not trust her with their money. In response, Honami decides to reveal the whole truth to everyone present and offers to step down as leader of their class as recompense for not telling them beforehand. However, astonishingly her classmates unanimously had a consensus and did not want her to do that as they believe in her. In response, she says she will continue working for the good of the class. Listening to the entire ordeal play out, Arisu, seemingly unsatisfied, told B-Class that a crime is a crime and that they shouldn't be so quick to trust her again no matter the reasoning, especially in their society. Seeing that her assault was not working, she praised the unity of B-Class and proceeds to say that she will continue her attacks soon. The school staff soon arrives and says that slander and rumors will no more be tolerated by the school as more students have been affected and started complaining, due to the rumors that Kiyotaka himself chose to spread. Upon hearing his name, she was amused and decides to take her leave.

When that was over, Arisu calls Kiyotaka and requests to speak with him. The first and only question she asks him was his rationality in helping Honami, as the rest of the questions had already been figured out correctly by her. Kiyotaka returns the question by saying that he was just playing his part as that's what she actually wanted by sending Masumi, telling her that he knew it was her plan for him to help Honami as a way to challenge him in the background. Although Arisu denies this at first, she continues by asking why he thinks that. He tells her that the beer can Masumi had passed to him had an expiry date far too old to have just recently been stolen which meant that it was the beer can that Arisu had caught Masumi stealing at the start of their school year. In order words, it was her plan to have Masumi reveal that secret to him, although in a very indirect manner. Arisu is impressed that he saw through all of it and says that he is indeed an enemy worth defeating as expected of him. She directly challenges him to face her next time, lightly threatening to expose his secret if he chooses not to do so. Kiyotaka thinks she won't resort to doing that either, even if he had rejected her offer. In spite of that, he eventually agrees to face her in the next special exam with her expulsion on the line as a means to remove her so she won't be able to reveal his past and disrupt his peaceful school life.

{{SpoilerSection|id=LNPlot|

Volume 10
On the first day of the supplementary Class Poll special exam, Arisu and Masumi happened to meet Kiyotaka. They discuss the current exam saying that it seems very unreasonable, with Arisu revealing that her father, the school chairman, has been removed from his post by dirty tactics which may explain why the exam is so different from previous exams. Arisu asks Masumi if she wonders why she was so interested in Kiyotaka, to which Masumi confirms. Arisu replies by saying that they knew each other from way before they came to this school. Masumi wonders if Kiyotaka was even a worthy opponent for her as she can't see that at all when even the other class leaders are insignificant to her. Arisu surprised Masumi by saying that he was different from the others and is not one to be underestimated. She then tells Masumi to leave so that she can privately talk to Kiyotaka to discuss their deal. She tells him that this exam isn't suited for their battle, so she wants to postpone it to the next exam. Seeing no reason to disagree, Kiyotaka agrees with her idea. She even reassured him that she will take no actions that will harm him in this exam at all. Thereupon, Kiyotaka wonders who she will expel from her class, and she tells him it's already been decided to be Katsuragi.

Arisu proceeds to put her plans into motion. Before meeting Kiyotaka by accident, Arisu had made plans to meet with Yamauchi in the night. Masumi was curious as she noticed that Arisu had seen her contact more often recently. She asks if Arisu 'likes' him, but Arisu reveals she has just been training a spy within C-Class and this exam is the perfect exam to test who he truly is and show everyone his true ugly nature. They soon decided to meet in the karaoke room. Arisu brings Masumi along for the 'date' saying that she is too embarrassed to go on a date with just the two of them. She tells Yamauchi that she wouldn't want to see him expelled so if he needs help he should ask her, successfully gaining his trust by playing to her words. Arisu tells him that he should target another student to save himself. Masumi, understanding the logic behind her plan, suggests Kiyotaka as a sacrifice. Yamauchi is afraid, as targeting someone else will make him the target as well. Arisu soothes his anxiety by offering 20 of her class' praise votes as protection to him so that he won't be expelled. When Yamauchi leaves, Arisu and Masumi discuss how strong Kiyotaka really is. Arisu says no other class leader like Katsuragi, Honami, or Ryūen has an ink of a chance against her but as for him, she wasn’t so sure. However, a part of her wants to be able to lose to him. Wondering how strong he really is, and hoping to see his full potential, Arisu plans to put him in a bind where he is going to be expelled by her hands to test his capabilities.

After a day goes by in the class poll exam, Yamauchi successfully amassed about half his class to vote for Kiyotaka due to Kushida's help and disdain for Kiyotaka. On Friday, the day before the exam, Yamauchi tells Arisu that he has been exposed as the ring leader and the target. He calls Arisu wanting to confirm that he will receive her class' praise votes, which she promises to. Previously, Hashimoto had previously advised her to not include Kei Karuizawa in the students targeting Kiyotaka but for some reason, she did it anyway. However, Arisu made it so through staggered timing, making sure to only include her on Thursday to ensure whether Kei was really helping Kiyotaka in the background, since Kiyotaka making his move on Friday eventually confirmed her suspicions. Arisu informed her faction that she had forgotten to tell them something very important up to that point. While it is not revealed what she said, it is inferred she told them that their praise votes will be going to Kiyotaka instead and that Yahiko Totsuka will be expelled instead of Katsuragi. The outcome of the class poll exam was Kiyotaka receiving many of A-Class's students' protection points thanks to Arisu's intervention, with Yamauchi and Yahiko being expelled.

After the exam, she meets with Kiyotaka telling him that this exam was most likely made to expel him as she had received a message from someone asking her to expel him. She was told the exam would likely have students from other classes being able to cast criticism votes on other class students making it easy to expel someone they didn't like in another class. After receiving this information, Arisu had decided to protect Kiyotaka from the very beginning. As they were talking about the outcome of the exam, Acting Director Tsukishiro comes up to them asking for directions and introduced himself, saying he will officially start in April. As Tsukishiro is about to leave, he attacks Arisu by kicking her cane away almost causing her to fall down but Kiyotaka successfully grabbed ahold of her and puts her down softly on the floor. Tsukishiro then grabs Kiyotaka ordering him to resign from the school himself. He doesn't retaliate causing Tsukishiro to leave. Arisu said it was a good idea not to fight back as although he told them that the cameras were not recording, it could have been a lie. Kiyotaka then remembers their past deal and challenges Arisu to a duel in the next exam, as with Tsukishiro here their battle might be interfered with so he wanted to get it done as soon as possible.

Volume 11
Arisu gives a monologue where she reminisces about her trip to the White Room with her father. Among the many children in the White Room, Kiyotaka Ayanokōji seemed to be the only one capable of calmly beating one opponent after the other in chess and was the only one to attract her attention. Her father didn't want the experiment to succeed because its success will likely force many other children to suffer the same unfortunate fate as Kiyotaka, and the children will similarly not receive their parent's affection. Arisu promised her father that she would defeat anyone from the White Room because she has the superior DNA she inherited from her extremely talented mother.

During the Event Selection Exam, she was the commander for Class A. Class A eventually won the exam thanks to her leadership and strategists and with her winning the last event - Chess, with Arisu defeating Kiyotaka. It also attracted much attention to Kiyotaka as he was capable of going toe to toe with her. It is later found out that Tsukishiro had somehow intervened with the school systems and tampered Kiyotaka's move to an inferior one, which Arisu was able to beat. Arisu was disappointed upon finding out and remarked that adults shouldn’t disturb children from having their fun. She politely asked Kiyotaka for another match in the library and to show her his actual move after the competition. When Kiyotaka played his actual move, Arisu found herself in check-mate. Both of them complimented the skills of the other with Kiyotaka remarking that in a few more games, she would win pretty handily against him due to her constant improvement.

In her short story, right before the start of the exam, Arisu found herself alone in the multi-purpose room with Kiyotaka. Her heart was palpitating just from being in the same room as him. Every time she tries to steal a glance at him, her body couldn't stop itself from being attracted and has great difficulties turning herself away. She acknowledges being a maiden in love and thoroughly enjoyed the newfound emotion from the bottom of her heart. It was revealed she couldn't sleep the night before and almost overslept due to the excitement of spending time with him. She stammered a bit since it was the first time having difficulty raising her voice for a while. Kiyotaka looked a bit troubled but replied, telling her that he meeting her was nothing but a coincidence in the first place. Arisu tells him that his meeting with her at this school might have been a coincidence, however, she was convinced that she would again meet him someday as it was meant to be fate, even if Kiyotaka didn't enroll. Arisu was talking to Kiyotaka non-stop as if yearning for him, one topic after another. That calm look he gave her and the sight of his pupils give her more pleasure.

Arisu asks herself whether she is afraid from waking up from this dream of herself with him. She knows that when one wakes up from dream and returns to reality, happiness will disappear for a moment. Fighting Kiyotaka and losing will result in despair, whereas winning so easily would leave nothing other than disappointment. She couldn't overlook a chance that it could happen, but it was fine.

Arisu asks Kiyotaka to fight with her using all he has got, and Kiyotaka responds with a nod. At the same time, Arisu could begin to guess what he had in mind. The thing that was keeping Arisu from enjoying herself to her fullest - Kiyotaka's true identity. They then discuss about the exam and how limited the leaders intervention is throughout the exam. But if the leader's influence was too large another problem would have arised - Kiyotaka's classmates identifying his true abilities.

The special exam was going to be a secret duel between Arisu and Kiyotaka, unknown to the teachers and other students. As the special exam was starting soon, Arisu went to the respective seats alloted to the leaders for the exam. She could no longer see Kiyotaka's face but doesn't want to be discouraged by that, because as long as both of them are in the same room, she could talk to him anytime and as many times she wants. Arisu sent a greeting to his direction in a voice so low that nobody could hear. She supresses the countinuous throbbing of her heart and now it was time her dreams will be realised.

Volume 11.5
Arisu gives Chairman Sakayanagi's number to Kiyotaka. She said that she knew Kiyotaka might run into trouble one day and might need her father's number and assistance. However, when Kiyotaka calls the Chairman, he says that he never gave his number to Arisu, meaning that she got it from somewhere else, displaying her resourcefulness and cheekiness.

Later on, during Kiyotaka's meeting with Sae Chabashira and Tomonari Mashima, Arisu appeared to have followed Mashima to the reception room. She told Mashima that she was also related to the incident; hence Mashima brought her along with him. To Kiyotaka, it seemed that she was just curious to know what was going on.

Kiyotaka invites the two teachers to take a seat, but since Arisu is crippled, Mashima offers his seat. As soon as Kiyotaka mentions that the meeting is taking place because of matters related to the Acting Director, both teachers are shocked and became apprehensive. On the other hand, Arisu shows an innocent smile to ease the tension and expressed her superior knowledge of the entire situation.

Arisu helps Kiyotaka explain the situation to the teachers. She says that she and Kiyotaka are childhood friends. The teachers were surprised to hear this considering their difference in status. After that, she tells them that the original winner of the chess event in the Event Selection Exam was in fact Kiyotaka, and someone from outside had stepped in to interfere and change Kiyotaka's move manually to an easier one in order to let her win. Chabashira got surprised upon hearing this. Arisu explains that all the chess steps were passed and processed by the school system first before sending it to participants. She says that Kiyotaka's father suspended her father, Chairman Sakayanagi, and sent Tsukishiro to the school as an attempt to expel him.

When Mashima asked who Kiyotaka truly was, Arisu tells them that he is an extraordinary person better than any other boys out there, saying that she knew about him better than any of them. She then states that she intends to stay by his side for the time being. Mashima argues that if she is seen giving special treatment to Kiyotaka, many questions might be asked. Arisu rebutted Mashima's words asking him if there was a problem with providing Kiyotaka special treatment. She says that although the school system revolves around a competition between classes, some may have friends or lovers from other classes who prioritize each other over their classes and sometimes, one's feelings can go beyond the boundaries of classes, forming mutually beneficial relationships with people from other classes. Even if she could only save Kiyotaka and leave behind her classmates in A-Class, the teachers can't blame her if she decides to do so. However, Arisu states that this favoritism exists for Kiyotaka only. After Acting Director is gone, she will not hesitate to crush his class. Mashima considers that as an acceptable compromise.

Later, when Kiyotaka leaves with Arisu, he finds her smiling. She says that she is smiling because this situation that presented itself seemed fun. Kiyotaka thanks her for coming and increasing his chances of persuading Mashima. Arisu requests Kiyotaka to let him rely on her to get rid of Tsukishiro, becoming something akin to a lifeline or secret protector for him.

2nd Year Volume 1
During the Partner Exam, Honami Ichinose invited students from both the first and second years to meet up and interact to improve their relationships. Arisu did not come to this event, knowing that all the students gathered would be those seeking partners not to win but to avoid expulsion. It was eventually found out that Arisu and Kakeru Ryūen were spending private points to attract the students to their side.

Arisu was seen in a cafe in Keyaki Mall along with Masumi Kamuro and Hayato Kitō. They were discussing how the Partner Exam was going to be conducted by the school. Masumi was on the phone with Masayoshi Hashimoto, relaying his findings to Arisu from across the table. Masumi reports that Ryūen had offered 100,000 points to a first-year that they have set their sights on and that he will increase the offer up to 200,000 if the number of pairs scores above 501 marks. C-Class was also straight-up offering 10,000 points to the first-years who declines A-Class's offer. Masumi asks to fight Ryūen's proposal with their private points. However, Arisu turns down her proposal for financial battles. When Masumi asks whether she plans to lose, she says there is a significant difference in academic power between Ryūen's C-Class and their own A-Class and that he has no other choice but to spend private points to overcome this exam. Arisu comments that Ryūen might have changed strategies: from buying his way to the top class using a million points to rising by increasing his class points.

Arisu says that Ryūen's strategy was not necessarily a bad one as he had forced Arisu to play along. However, he only targets the same students A-Class is going for, which is his miscalculation. As C-Class is the inferior class, Ryūen should have focused on the more academically gifted students. Arisu then decides to counter with a strategy to pay the same amount of points but not partner up with students or give them the points. This way, Ryūen will be forced to offer more points and lose the money game while A-Class is not involved at all. Masumi does not understand the logic, so Arisu explains by saying that by using her strategy of pretend-money, Ryūen will have to offer up more money. For them, however, they will be able to reel in students with their A-Class reputation. While Ryūen simply thinks that their good reputation is nothing more than a label, she still sees that as a miscalculation that can be exploited on his part. Masumi still does not fully understand Arisu's strategy but is told to follow the instructions and rest assured. Arisu hopes Ryūen doesn't self-destruct afterwards, wishing that her upcoming opponent was somebody worth facing off against and that she won’t be disillusioned.

2nd Year Volume 2
Feeling the need to make a small group quickly for the Uninhabited Island Exam, Arisu contacted Honami Ichinose on a particular day to discuss about group formation. Arisu's quick invitation was a strategy so that Honami won't have much time to think and be forced to agree to her terms. Since it was already Friday of the first weekend when the group formations had started, Honami decided to accept Arisu's invitation anyway and arrived at the designated site, where the latter was already waiting for her. Upon arrival, Arisu questioned Honami about why she agreed to meet up with her. Honami replied saying that she didn't have anything else on her schedule. Arisu pushed the matter further, telling her that she has done terrible things to her, and she wouldn't be surprised if Honami hated her. Realizing that was not what Arisu meant by her previous question, Honami conveys her feelings about how she isn't bothered by the terrible things Arisu had done to her as she wants to let bygones be bygones. In fact, Honami explained how she did not harbor any hatred or resentment towards the former for exposing her past or betraying her trust but actually genuinely thanks her for teaching her a valuable lesson and for exposing her naivety. Honami said she didn't think whatever Arisu had done was anything excessive, telling the latter that it had helped her reflect on what happened during middle school and come to terms with her shameful act. Hearing this, Arisu described Honami as a good person, to which Honami got a little embarrassed. Honami started scratching her cheeks lightly and averting her gaze as if she couldn't handle the sight of Arisu gently gazing at her.

Arisu understands that Honami wants to quickly move on to the main topic of the discussion. Hence, she decides to just do that and respect her wish. She tells Honami that it might not be a very comfortable topic of discussion for her, which caused Honami to silently pray for Arisu to go easy on her. Although Honami was not comfortable with the direction the talk seemed to be heading towards, Arisu started with it anyway, explaining Class-A's predicament before the Uninhabited Island Exam, saying that Class 2-A was naturally feeling the danger as Kakeru Ryūen's Class 2-B is approaching them once again. After Arisu stated her concern, Honami, who was the leader of Class 2-C, was then asked by the former about her thoughts on that potential problem looming on the horizon. In more ways than one, Arisu had mercilessly pointed the other dilemma besides Class 2-A, where Honami and her Class 2-C were also being left out in the cold from both Class 2-B led by Ryūen and Suzune Horikita's Class 2-D. Arisu showed a deliberate smile towards Honami as the latter could not answer momentarily and started fanning herself with a bitter smile. Arisu started feeling that the conversation is going according to plan. After being given some time to process what she had said, Arisu makes Honami admit and acknowledges the fact that Class 2-C was feeling excluded and ostracised from the two classes, which was not a good sign as that was the result of her multiple failures to lead.

Arisu also made Honami feel the numerous and potentially dangerous students that are hidden in D-Class, including Yōsuke Hirata and Kikyō Kushida who have strong communication skills as well as having well-balanced grades, along with Ken Sudō, who is the only one to get an A+ rating in physical ability in the entire cohort. They also have hidden cards like Rokusuke Kōenji and Kiyotaka Ayanokōji, whose extent of abilities are still unknown. Arisu concluded by saying that D-Class is now being led by Suzune Horikita who has excellent academic and physical abilities and has recently joined the Student Council. Arisu forcefully makes Honami reaffirm her current situation of being left out in the cold and feeling unsettled that she isn’t progressing at the same rate as then, telling Honami that her class will inevitably fall to D-Class sooner or later. As Honami tried to deny it, Arisu simply took the words from her mouth and made her swallow back what she was about to say. Arisu then decided to praise Honami after shattering her by saying that her class has something that no other classes can beat and something extremely potent, which was unconditional trust between classmates. She acknowledges and recognizes Honami for being able to establish such a feeling and said that it would be extremely important in a partnership between classes.

As Honami remained speechless and silent by that statement, Arisu attacked further, asserting that it was almost nigh impractical to win with simply believing in these kinds of vague things no matter how hard the former tried to make such abstract values work successfully as they would always fail in the end. Arisu continued to belittle and denigrate Honami, explaining that three of the four classes (A, B, and D) had clearly been improving and increasing their strength over the year, while the same could not be said for Class 2-C as she did not see much growth happening in it. Arisu didn't argue against the notion of them growing up but stated it was a matter of the amount of growth in how much they have grown, implying their improvements were too little and minuscule to compare with Classes 2-A, 2-B, or 2-D. Honami says that her class won't lose to any of the other classes. Arisu, not believing a word she says, counters her statement saying that if Honami had looked at the OAA app and analyzed very carefully, it was evident at first glance that Class 2-C was the one who had grown the least among the four classes after comparing the overall abilities of when they were 1st years to 2nd years. Arisu, surprised, thought Honami would've already done that level of analysis as her and reached the same conclusion like she did, which caused her to cast doubts on whether Honami even knew the facts all along and pretended not to notice or did not even dare check them for fear of facing the cruel reality of Class 2-C's situation. Being driven into a corner by Arisu, who came off as harshly critical of her and her class, Honami recalled when she was alone with her and how the two of them were like a child and an adult arguing back and forth, respectively.

Arisu repeatedly attacks Honami's weakness. However, she also acknowledges her ability and potential to be an intelligent student. Arisu states that Honami failed to use her true strengths to the fullest effect whenever she was in an unfavourable situation outside her strategic control. She confidently declares that Honami stood no chance in winning against any of the three classes due to how less Class 2-C's growth had been the last year. Hearing enough of the argument, Honami asked Arisu if this discussion was what the meeting was all mainly about finding faults with her and why she had been invited to the café. Arisu replied that it was not the real reason Honami had been given an invitation in the first place, explaining how she could've persisted with this kind of conversation anywhere else that is not related to the meeting and not waste her precious holiday time on it. Finally deciding to get to the main point of the discussion, Arisu then asked Honami to cooperate with her between their two sides, Class 2-A and Class 2-C, much to the former's disbelief and astonishment at the unexpected proposition.

Bewildered by the sudden proposal, Honami was asked again by Arisu to consider the offer as this was the only way for her to catch up to Class 2-A. Arisu tries to reason with her that a cooperative relationship between their two classes was not entirely a bad idea for either side to have, taking the example of Honami's cooperative relationship with Suzune of D-Class when they were 1st years. She quickly explains this before Honami can give her say in the matter. Arisu was able to ultimately deduce how her class alliance with Suzune had ended due to recent achievements of Class 2-D having given that group a lot of incredible momentum going on for them to catch up when it came to accumulating more class points than any class while being the most successful of the four classes last year despite starting from nothing but zero. Arisu wanted Honami to realize that this had happened solely because of her own negligence with her classmates, where they took a step back and fell down from Class 2-B to Class 2-C was what allowed Suzune to think there are no longer any advantages in continuing to work with them. By pointing everything out at her, Arisu made Honami admit that partnerships didn't always last forever.

Arisu wanted a partnership with Honami because of the massive difference in points between A-Class and C-Class. She reasoned that this partnership is of value when the powerful weapon Honami possesses known as "trust" was what she greatly wants in an alliance and could care less about the shortcomings of her fighting strength. In other words, Arisu emphasized to Honami that it's a very important factor to consider as worthwhile when seeking to create an alliance based around trust, thinking she can be entrusted to watch her back. Honami, however, informs her that Class 2-C is currently in a bad situation where they don't care much about the weapon being "trust" anymore. On the other hand, Arisu cast her doubts if Honami and her class will really go as far as to relinquish their "trust" and throw it away after spending one year of building up such a weapon and developing it. Arisu informed Honami that if Class 2-C's betrayal occurs, it will be the latter's own fault for having misjudged the former.

Arisu was then surprised when Honami took a shot back at her by threatening and floating the idea of allying with the other classes to take down A-Class, which Honami states that she knows that was something Arisu was trying to prevent by approaching her in the first place. Seeing how Honami was able to see through her actions, Arisu praised her genuinely and admitted that she truly underestimated her. This causes Honami to blush. Additionally, she gave in to Honami's demands of securing private points for them so C-Class will be able to protect those on the precipice of expulsion and eventually was able to secure their class alliance with a handshake.

2nd Year Volume 3
In the midst of the Uninhabited Island Exam, Kiyotaka searched and eventually stumbled onto Arisu underneath a parasol on the beach. They exchanged pleasantries as Kiyotaka asks how she was doing. She felt that they’re doing reasonably well considering the handicap of her bad legs. The school had made an exception and allowed their group to earn Early Bird Bonuses after taking into account her condition. They discuss about Kōenji who has recently moved up to second as she praised his prodigious talents.

She signals for Kiyotaka to join her underneath the parasol as they turned their attention back to Kouenji who was winning handily in his event. Kiyotaka uncharacteristically asks Arisu for a request which piqued her interest. They discussed about the retired students as Arisu quickly deduced what he was after. She voices of how it’s prudent not to lose second-year Class Points to the other levels but since it wasn’t affecting her class directly, she sees no need to intervene.

Arisu asks if Ryūen was privy to his plan which he confirms. Using her quick intuition, she counter-offers and proposed a favour from him to extend her cooperation. Kiyotaka accepts and says he'll contact her soon.

In her monologue, Arisu found herself objectively analysing the effects of the exam. Soon after, Kiyotaka approached her as she felt her cheeks soften. She wasn’t surprised at how unperturbed he was considering his capabilities. As they talked about Kōenji and how Kiyotaka wanted to participate in that event, Arisu laments that even without personal feelings, she wanted to see Kiyotaka taking the honours instead. She invites him over to the parasol as she felt that by being close to him, it would make it more enjoyable. She tries to wash away the poignant thoughts of their direct interaction in school being limited and disregarded any other frivolous contemplation. She finds it pitiful that he doesn’t share the same sentiment as her heart continued racing, thinking about their conversation ahead. She always finds herself wishing it could last forever, even if it's a moment longer.

2nd Year Volume 4.5
During the summer vacation, Arisu found and met Ichika Amasawa on the cruise ship. Arisu blatantly told Ichika that she doesn’t view her as a threat, but instead as a failure when compared to Kiyotaka. Ichika successfully recognises that Arisu is trying to agitate her and retaliated by accepting her challenge before walking away. In truth, Arisu finds Ichika to be extremely dangerous and couldn’t afford to allow her to run free which prompted her to reign her in before she does something detrimental. }}

Abilities
Along with Kōhei Katsuragi, Arisu leads A-Class and has a loyal group of followers that would faithfully do everything she orders. Despite her limited physical ability due to birth defects, Arisu is notable for her talents as being the only person Katsuragi reports to, despite his own outstanding academic prowess and leadership skills. Manabu Horikita, the former Student Council president, even praised her phenomenal holistic management of her class, such as being able to stand out from the rest of the classes in terms of class points despite only having a handful of weeks to establish her control, and personally invited her for a chat to commend her achievements.

She is also shown to be resourceful as when she was unable to go on the school cruise, she had Masumi Kamuro conduct research on certain students and Masayoshi Hashimoto to physically manifest her plans in her stead.

Academic Abilities
Arisu is known for receiving great scores throughout her school-year and has the highest overall score for her year in the OAA. Even Manabu Horikita, the previous Student Council president at that time who has extremely high standards, praised her grades in the recent midterms. This was notable as the only other person he had ever been seen complimenting was Kiyotaka Ayanokōji, who is extremely intelligent and skilled in manipulating his academic ability in his own right. She easily boast one of the highest academic and adaptability grades in the entire school's history. During the Partner Exam, where many questions had difficulty equal to college questions, she was acknowledged by Kiyotaka for achieving high grades in them, though she didn't go to any sort of facility like White Room.

Intellectual Abilities
Arisu is known for her vast intelligence, which even garnered praises from many people from other classes such as Honami Ichinose, the representative of B-Class who reported to her teacher Chie Hoshinomiya that Arisu is someone they had to actively watch out for.

She is also very manipulative, cunning and perspicacious in her plans which can only be rivalled by Kiyotaka. She knows how to play to her charm and beauty and isn’t above using them to get to her objectives such as expelling Haruki Yamauchi. One of the way she does this is by playing to the strength of her allies while targeting the weaknesses of her enemies, crippling them before them can attack. For instance, she was able to emotionally scar Honami by revealing her secret, effectively taking out the leader of the second best class and their chances of competing with her. Additionally, she played Honami to her advantage by exploiting Honami's kind and forgiving nature by forming an alliance with them before other classes could.

She is also very good in chess, perfectly capable to be on the national level and even cause difficulty for Kiyotaka who was trained from young to be virtually perfect in it. She is easily able to factor in her opponent's idiosyncratic thought processes in her plans, thinking more than 10 steps ahead of them and countering them in the span of seconds.

Her deduction and analytical skills are one of the highest in the entire school and on par with Kiyotaka when he is serious. She is easily able to lead and have dominion over most of her classmates in A-Class who are full of distinguished students and individualistic personalities and have them obey her every command.

List of Short Stories
Short stories involving Arisu Sakayanagi are listed below:

 *: Scene not included in light novel (extra plot).

Quotes

 * (To Kiyotaka Ayanokōji): "It's been quite a long time, Ayanokōji-kun. It's been eight years and 243 days actually "
 * (To Kiyotaka Ayanokōji): "Oh, it's quite all right that you don't know me. But I know you. We have a strange sort of bond, you could say. To reunite with you in a place like this... To be honest, I never thought I'd see you again. But now, all the mysteries have been cleared away. The island, the cruise ship, and Class D's expulsion uproar. I couldn't imagine that everything was on account of Horikita Suzune. So you were pulling the strings."
 * (To Kiyotaka Ayanokōji): "Sorry for laughing. I didn't intend to insult you. I know quite well how incredible you are. I've been looking forward to this. I'll be able to realize my dearest wish by destroying the greatest masterpiece that your father ever made."
 * (To Honami Ichinose): "Only by a slim margin. Two points. I think we were just about evenly matched."
 * (To Kakeru Ryūen): "I'm here purely by coincidence."
 * (To Kakeru Ryūen): "This is a fascinating conversation. Someone in Class D is getting in Class C’s way, are they? I heard rumors that Dragon Boy-san was searching for such a person, but is that really true?"
 * (To Kakeru Ryūen): "My, my, you don’t like it? I think it’s a wonderful nickname. Sorry. Anyway, there’s something here that I don’t quite understand."
 * (To Kakeru Ryūen): "Someone in Class D saw through your plans and defeated you. Is that all there is to it? This school is fundamentally designed to pit classes against each other. You and I have clashed numerous times in this manner. I don’t know who this Class D student is, but they’re employing excellent strategy by remaining anonymous while waging war on you. Are you really going to expend all this energy on interrogating an unrelated student? Honestly, I can’t see your actions as anything but rather pathetic."

Name Etymology

 * The name Arisu consists of kanjis that mean "exist" (有) (ari) and "tree, nest, rookery, hive, cobweb, den" (栖) (su).
 * Arisu's surname Sakayanagi consists of kanjis that mean "slope, hill" (坂) (saka) and "willow" (柳) (yanagi).

Trivia

 * In the light novel, Arisu debuts in Volume 5; however, in the anime, she first appears in Episode 1, which chronologically takes place much sooner than the light novels.
 * Arisu's ranking in the "Female Character" category for 's  guidebook are as follows:
 * For the 2nd Year arc, when asked about her aspirations for the next year, she answered  'To lead a school life that's interesting... And protect my beloved person from unwanted vermin I suppose.'
 * From her student database:
 * Specialties: Chess
 * Hobbies: Observing Kiyotaka Ayanokōji
 * Intimate students: Masumi Kamuro
 * Incompatible students: Kōhei Katsuragi
 * Favorite foods: Pasta
 * Dislikes: Filthy things
 * Her OAA in the first year would be:
 * Academic Ability: A (93)
 * Physical Ability: D- (24)
 * Adaptability: B (71)
 * Social Contribution: C (55)
 * Overall Ability: B (62)