Kei Karuizawa

Kei Karuizawa is one of heroines of the You-Zitsu series as well as a student of Class 2-D of Advanced Nurturing High School. She is a prominent figure in class and is considered to be the girl's leader of Class D.

Appearance
Kei is a teenage girl of average height with waist-length blonde hair that is tied in a ponytail and purple eyes. Her school uniform consists of a light blue dress shirt below the red school blazer with rolled-up sleeves and a short white skirt. She walks in standard school shoes with light blue calf-length socks. She predominantly wears a blue ribbon around her collar. In a more casual situation, she simply wraps her school blazer around her waist and rolls up her dress shirt sleeves.

Personality
Kei is an outgoing person who spends most of her time with the girls at school and Yōsuke Hirata (her boyfriend). Typically she speaks for the girls in the class, acting as one of the leaders along with Yōsuke and eventually Suzune Horikita.

She seems to be a bit of a mooch, as after spending all her points from the first month and D-Class not receiving any, due to their penalties, she asked the girls of her class to lend her some money to buy the 'essentials', managing to gain at least 2000 points from Kikyō Kushida.

She doesn't take notice of less prominent people in the class. This was seen when she mentioned Kiyotaka Ayanokōji being "invisible" after Suzune nominated him as a guard with Yōsuke. Ironically, she befriended him in the light novels and they were very close, even being impressed by his abilities and going on a first name basis as she eventually starts to develop romantic feelings for him.

Background
Kei is a prominent figure of class. Being gifted with an attractive personality, she is considered to be the girl's leader of class D. Her development in the story is worth reading. Despite her looks and attitude she displays and the relationship between her and Hirata, she has her bunch of secrets that she cannot afford to reveal to others.

Plot
In the anime, Kei, like the other first years, listened to the speech given by Manabu Horikita, welcoming the first years to their new school. She was seen in the class talking to Satsuki Shinohara before Yōsuke Hirata asked the class to introduce themselves, agreeing with the idea.

After the teacher Sae Chabashira walked in and introduced to the class the system in which they are supposed to live in now, Kei was surprised at the fact that they received 100,000 private points, to begin with. She was seen talking with Maya Satō and Chiaki Matsushita about clothes and jewelry shopping after the classes that day. At the start of the new month of June, along with the rest of D-Class, Kei was shocked when Class D did not receive the monthly allotment of points, looking depressed throughout the explanation of S-Points and the reason D-Class didn't get any points.

At some point later, Kei went to the pool with the rest of the class, getting especially close to Yōsuke, which possibly indicates that they have been dating since. She tried asking Kikyō to lend her points along with some other girls of the class to buy herself the 'essentials', in which at least Kikyō complied with the demand. She is seen getting closer to Yōsuke, then proceeding to take the mid-test exams and passing with an overall score of 75.

During the anime pool filler episode, Kei saw Suzune walking out of the apartment building, claiming how there were rumors she had died, since no one had seen her over the summer break. Kei then left, dragging Yōsuke with her after Suzune expressed her disinterest in hanging out with the rest of her class when being questioned about it.

Later Kei, like all the other first years, took part in the school cruise, where she was seen calling Yōsuke over to hang out with her friends. When the cruise ship headed to an island, all first-year students were told they need to survive for more than a week with basic materials. Kei got into an argument with Teruhiko Yukimura about the hygienic materials they would need for survival, specifically the need for a toilet. Kanji Ike joined the argument as well, but after setting up camp, he surprised Kei, as he apologized for his words since he went through a similar event when camping as a child. Touched by this, Kei apologized for not understanding his reasons as well.

Towards the end of the survival test week, Kei was found crying in the girl's tent as her underwear was apparently stolen. The girls of her class had Yōsuke check all the boys and their luggage to find it. After minutes of searching, Yōsuke then found the underwear in Kiyotaka Ayanokōji's luggage but refrained from telling anyone, since he (rightfully) suspected that Ayanokōji was set up by someone else.

The next day, Kei and the other girls told the boys to build a separate camp from them because of the incident the day before. Kei had Yōsuke watch over the boys in the class while they moved, but Suzune requested that another boy should check over Yōsuke, since he could potentially be a threat as well. Though Kei defended her boyfriend, she agreed to the request but wondered which boy should help as all the other boys are deemed untrustworthy. Suzune then proposed that Kiyotaka be the second guard since he doesn't seem to have a lecherous side.

Kei recalled that Kiyotaka was often 'invisible' during class, admitting to herself that she barely noticed him being their classmate. In the same night, somebody had started a fire at camp by burning the survival test manual, Kei and the other girls questioned the culprit's identity, first suspecting that one of the boys must have done it. They soon, however, suspected Mio Ibuki because of she was nowhere to be found during the incident. They later learned that Suzune had dropped out of the test because of a fever. They then discussed Mio's motive and whether or not she was the actual culprit and C-Class' leader since her class had dropped out of the test earlier in the week.

The next morning, Kei was seen cleaning in the camp along with the girls. At the time of the class points announcement, she and the entire class were shocked to hear that D-Class came in the first place. Later that same day on the cruise ship, Kei and the others thanked Suzune for her brilliant plan, though, unbeknown to them that Kiyotaka actually planned everything but gave Suzune all the credit to boost her popularity in the class cementing her place as a dependable leader.

{{SpoilerSection|id=lnvol4|

Light Novel Volume 4
Much to the surprise of everyone, there was another special exam on the ship after their return from the survival island. In this exam, the objective was to find a person deemed as the VIP hidden among the members as the batch was divided into 12 groups based on the Chinese zodiac signs. Kei was placed in the same group as Kiyotaka, Teruhiko Yukimura, Hideo Sotomura, and students from other classes such as Honami Ichinose from Class B, Machida from Class A, and Mio Ibuki and Shiho Manabe from Class C. Kei couldn't hide her dissatisfaction when she saw Kiyotaka and others as her groupmates.

Kei was seen abstaining from the group discussions to expose the VIP, but was often flirting with the handsome Machida from Class A, which eventually pissed off Manabe and her friends. Machida seemed to have taken an interest in Kei due to her cuteness and depicted a protective stance towards her. Manabe and her friends then brought up a previously unresolved matter of Kei having shoved one of her friends, Rika, earlier in the cafeteria and asked her to apologise. Kei feigned ignorance with respect to the accusation and kept using Machida as her shield, which further pissed Manabe off.

After one of their group meetings, Kiyotaka and Teruhiko saw Kei getting cornered in the emergency staircase and being confronted by Manabe and others. Manabe was still accusing Kei for the incident that happened with Rika, but Kei, being stubborn, denied the fact that she had pushed Rika. As the argument heated up, Manabe and others lost their patience and started physically hurting Kei. Even though they began by just shoving her shoulder, this caused Kei to show strange reactions such as breathing raggedly and curling into a fetal position. Manabe and her friends then decided to go a step higher and proceeded to grab Kei's hair, forcefully pulling her up, and saying that they wanted to hit her face. This act of physical bullying led Kei to lose her previous arrogance and attitude, causing her to begin shaking and tearing up to the point where the previous Karuizawa Kei seemed nothing more than a façade. Before the situation could turn worse, Teruhiko, who couldn’t bear to watch it anymore, interrupted them. The situation improved after Kiyotaka said that he had seen a teacher coming, and that it would be best for Manabe to leave. They then left, and Kei recovered from her trauma. She then brushed off Teruhiko, who showed concern towards her, ordering him and Kiyotaka not to let anyone else know about this.

Kiyotaka percieved Kei's reactions as extreme, so he asked Hirata and learned that Kei had been bullied since elementary school. He recognised Kei as a capable person, due to the fact that she had been able to cover up her past using a new persona until now, so he decided to make her his pawn who would obey his orders and work for him in secret. He anonymously testified to Manabe about her issue, then used an invite from Hirata to lure Kei to the ship's lowest level near the engine room and let Manabe's group get revenge for their friend. After Manabe's group left, he approached Kei and told her that he would save her in exchange for obeying all his orders. Kei tried to put up a strong front, but lost all will to resist when Kiyotaka glared deeply into her eye, showing the extent of darkness in his. He informed her that he had secretly taken a video of Manabe bullying Kei, which he would use to protect Kei by blackmailing Manabe's group incase of a situation. Forming a relationship with Kei, he made her go along with his plan, leading to Class A wrongly guessing the group's VIP, to win in his group.

Light Novel Volume 4.5
Two days before the end of summer vacation, Kiyotaka summoned Kei to a rest area where nobody was present due to the heat. He inquired about her plans for tomorrow and she shared that she was going to sleep all day because she had no more points to spend. Kiyotaka mentioned that she would receive 500.000 points next month and teased her a little about her habit of spending points. After Kiyotaka told Kei the primary reason for calling her out, which was to ask her a favor, Kei expressed her dissatisfaction because he had not apologized earlier for calling her there on such a hot day. He gave her a bottle of tea which she reluctantly accepted. Kiyotaka said that he had been invited to the pool by his friends on the last day of summer vacation. After replying that she wasn't interested in swimming, Kiyotaka asked her if she liked swimming or not, recognising that due to her circumstances, she couldn't swim openly because of the possibility that someone might see her scar. Kei answered that she's probably forgotten how to swim as she hadn't done it for years now.

While Kei intended to question what Kiyotaka wanted because his holiday plan had nothing to do with her, he asked her if the school truly did not know about her past bullying. This made her angry because it was a sensitive topic for her. After Kiyotaka insisted that this was relevant, Kei finally replied that the school didn't know, and even if they investigated the matter, they wouldn't be able to find any evidence. She admitted that she was grateful to the people who had bullied her and to the school that had covered it up, because that's why she was able to grow into a new herself. Believing that Kei wasn't the kind of person who would resort to violence or intimidation, Kiyotaka forbade her to do anything that constitutes as or supports bullying. Kei wondered why she felt surprisingly at ease after telling Kiyotaka about her past, recognising it as odd. She asked if the way he was acting at that moment was his real personality, adding that at first she believed that he was just a gloomy guy but now he was assertive and very direct. He told her to just keep her eye on him to determine what kind of person he was if she was really interested. After that Kiyotaka began to tell Kei about Yamauchi, Ike, and Sudou's plan to peep on the girls tomorrow.

The next day, which was the last day of summer vacation, Kei went to the pool with two of her friends and headed straight towards the locker room, finding the vent Kiyotaka had unfastened and replacing the memory card on the camera. When it was almost closing time, Kei approached Kiyotaka who was then alone, slapping his back from behind before handing him the memory card she had taken from the camera in the locker room. She asked Kiyotaka about his plans and if he was really aiming for Class A. He answered that he was thinking about having someone expelled from the school, which bewildered Kei. She thought that Kiyotaka was definitely not normal, something that she could gauge from looking into his eyes.

While waiting until the locker room was empty, Kiyotaka suggested Kei to swim considering that the area was deserted except for a few lifeguards. Kei refused, but after Kiyotaka said it was an order, she had no choice and reluctantly removed her rash guard while saying that she hated him. Suddenly Kiyotaka grabbed her arm and before she could protest, he shoved her into the pool to which she shouted at him. Following her outburst, Kiyotaka offered his hand to get her up and asked if she had fun. Kei said she didn't, before pulling him into the water without warning and laughed.

Light Novel Volume 5
At the beginning of September, just a month before the Sports Festival, Class D began making comprehensive preparations for the participation table during the homeroom period when Kiyotaka instructed Kei to object to Horikita's plan, and to then ask Kushida for her opinion. Though Kei agreed with Horikita's plan to pair up the stronger athletes with the weaker ones, she still conducted the order perfectly, and due to her influence in the class, many joined her side. Thus, Hirata concluded that the class should vote to settle that matter. After classes ended, Kiyotaka exchanged looks with Kei but she went out of the classroom with two of her friends. Believing that she might not have understood his intention, he left the classroom, getting surprised when he found that Kei was waiting for him by the main entrance alone. Kiyotaka complimented her for the improvisation but did not answer her when she asked him about his real intention. This angered her because it seemed like he treated her like a dog. Kiyotaka then told her that a traitor would emerge during the Sports Festival, and when the time came, she would understand.

At the beginning of October, during the Sports Festival, Kei had been chosen as one of the horsemen for the first-year girls' Cavalry Battle. When she noticed that Ibuki from Class 1-C led a surprise attack on Horikita, Kei commanded Shinohara to help Horikira's unit, but before they could reach Horikita's unit, Ichinose's unit stopped them. As Kei instructed her unit to go forward, she thought to herself that it wasn't like her to do troublesome things, but for some reason, she did not want Kiyotaka to see her defeated. Kei managed to react well to Ichinose's movements and launched a counterattack, successfully snatching her headband before she fell off.

After first-year males Cavalry Battle, Kei called out to Kiyotaka using his first name without any honorifics, surprising him. Kei expressed her worries for Horikita even though she did not like her as of her mighty attitude, but could still empathize with her due to her experience of being targeted by bullies. During the lunch break, Kei and Hirata joined Kiyotaka for lunch while discussing Ryuuen's strategy as well as the possibility of a traitor. Following the race between Student Council President and Kiyotaka, Kei couldn't hide her shock from witnessing his speed against Manabu. As other students started approaching them, Kei decided to move out of the way for the time being.

Light Novel Volume 6
In mid-October, two weeks after the Sports Festival ended, Kiyotaka noticed that Kei cast a strange look in his direction before she exited the classroom. As her short, fluttering skirt caught his attention, his name was called by one of his classmates - Satou Maya. Later that night, Kei called Kiyotaka while he hung out in his room and immediately asked if Satou had confessed her feelings to him. Kiyotaka wondered how did Kei knew and she replied that Satou told her in advance that she was going to confess to him. Kiyotaka said that it had nothing to do with her but she argued that she didn't want rumors floating around, and wanted to be sure that Kiyotaka wouldn't tell Satou anything about her incase they started dating. Upon confirming that Kiyotaka and Satou only exchanged contact information and he didn't have feelings for her, they ended their phone call after Kiyotaka reminded Kei to erase records of their conversations from her phone.

A few days later, when Kiyotaka, Horikita, Hirata, Kei, Kushida, and Sudou had gathered for a meeting at Pallet café regarding the upcoming Paper Shuffle Exam. In a different classroom Ryuuen was interrogating Manabe and her friends, asking why they betrayed him. Having no other choice, Manabe told Ryuuen the details of what had happened on the cruise ship, telling him everything including how they were in the same group as Kei and the truth about Kei's past. Manabe explained that she had to spy because she had received threats claiming to expose them unless she followed the instructions.

On October 20, after chatting with his friends and speaking with Horikita, Kiyotaka received a text message from Kei who was reporting on her investigation regarding Shiina Hiyori, confirming that Hiyori was walking around that day asking people if they knew how much sugar Hasabe put in her coffee. Kiyotaka then told her that Horikita was going to contact her the next day, and that they had planned to meet around 8 p.m. Kei wondered why it was so late, to which Kiyotaka answered that he was going to be busy because he was going to watch a movie with his study group. Kiyotaka asked Kei for another favor for which she complained, but later agreed. As they exchanged their goodbyes, Kiyotaka thought that their conversation was over, but he received another message from Kei. It was a cute strawberry shortcake sticker with a bunch of candles on it, along with the additional message of 'Happy Birthday'. Kiyotaka had thought that no one would notice his birthday this year, and was thus surprised when Kei wished him. When he deleted all the texts from their conversation, he felt hesitant to delete the birthday sticker she sent. Following that, he accessed Kei's profile and saw that her birthday was March 8, and he decided to remember it.

At the movie the next day, Kiyotaka ran into Kei and Satou. Kei insisted that this was just a coincidence but Kiyotaka didn't buy it. After watching the movie, the group went to a karaoke bar where everyone from Class D had gathered. Following Kiyotaka's instructions, Kei accused Kushida of acting a little too nice when they were in the middle of studies and pretended to get pissed, proceeding to pour her grape juice over Kushida, staining her blazer. Hirata asked Kei to apologize to Kushida, just as she was about to leave. Later Kei offered to pay for Kushida's blazer to be cleaned.

On the first day of the special exam, as Kiyotaka walked into the hallway on his way to the classroom, where he met up with Satou who had been waiting for him. After they exchanged greetings, Kei appeared and greeted Satou, and pulled Satou to go with her to get a drink before class. Hirata who watched that display mentioned that Kei was a surprisingly jealous person. Kiyotaka didn't understand it, so Hirata explained it further by saying that Kei had been paying more attention to Kiyotaka lately.

Light Novel Volume 7
Mid-December has passed. Following the meeting of Kiyotaka and his father, Kiyotaka resolved to put an end to all his schemes, which included cutting off his ties with Kei. He called her through the phone and asked what she was up to. She didn't believe him, but she knew that Kiyotaka wouldn't call her without a reason. Kei began questioning why Kiyotaka was helping Class D from behind the scenes. He revealed that he had no choice but to lend Class D a hand, but then he apologized to her saying that the reason he helped the class just disappeared and this would be the last time he contacted her. His words made her confused and she couldn't formulate a proper response, but Kiyotaka assured her that he would still protect her if anything happensn as it was a promise. Kei didn't understand why he was saying all of this so suddenly, why he had become so cold. He simply replied that this was just the extent of their relationship. Before they ended the call, Kei seemed to have something to say but didn't follow up on that.

After the closing ceremony of the second semester, Ryuuen began to execute his plan. He had called Kei out to the rooftop, threatening to expose her bullying past if she didn't come. Around 2 PM, Kei showed up on the rooftop and demanded to know what Ryuuen was after. He wanted to know the identity of X, the person controlling class D from behind the scenes, to which she answered she had nothing to say. Despite being threatened that he would reveal her past, Kei argued that if he exposed her past before he could draw the answer out of her, there would be no incentive for her to tell him anything and his search for X might be delayed. Realizing that Kei wouldn't budge no matter what, Ryuuen instructed Ibuki to hold Kei down and ordered Ishizaki to fill the buckets with water. When Kei realized what's about to happen to her, she tried to break out of Ibuki's hold but the effort was to no avail. Following Ryuuen's request, Ishizaki dumped water from the bucket onto Kei's head, making her collapse on the spot and tremble. As she internally relived the bullying of her past. Ryuuen grabbed her bangs and lifted them up, claiming that she's the sort of person conditioned to receive bullying, and that human nature could not be changed so easily. He then dumped the other bucket of water on her, asking again who's the one protecting her by shutting down Manabe's group. Kei just shook her head and denied revealing it over and over. Ryuuen who felt amused continued his torture, admitting to himself that he's breaking her for his own pleasure.

After they had dumped water on her multiple times, darkness started to rear in her head. She began to blame herself, wondering why she was being bullied, questioning why she was even alive and what she did wrong while Ryuuen laughed in front of her. She was scared, and the bullying she received in the past continuously replayed itself in her head. As she was recalling her past, she wondered if Kiyotaka had abandoned her. Noticing that she trusted X quite a fair bit, Ryuuen then revealed that she was deceived, telling her the truth of the shipboard exam, wherein X had deliberately set up her bullying to acquire the evidence, that she wasn't saved but trapped. Those words caused Kei to fall into extreme despair.

Ryuuen told her that there was still one way to save herself, which was to tell him about X's identity to which he promised that he would never get her involved again. Feeling despair and rage at being betrayed, and her heart wishing to be saved, her lips started moving while still trembling. But to Ryuuen's surprise, Kei shouted that no matter how many times he asked her, she would never tell him, she had no intention of saying it from the very beginning. Even if starting tomorrow she lost her place at this school, and even if she continued to suffer, she would never give Ryuuen the name.

Ryuuen felt bewildered asked why she still covered for X even though she knew that she was just being used. Kei answered that she didn't understand as well, she just wanted to act cool until the very end. Despite being baited, she didn't betray him. She was broken but still confident. If she could help Kiyotaka gain the peace he desired, that was not so bad with her. Her life had never been as interesting except when she worked with him, things got exciting and she had fun. Although she didn't understand most of what she was ordered to do, she felt like the heroine supporting her hero from the shadows. That's why she regretted nothing. Ryuuen declared that she's a person worthy of his respect.

As Kiyotaka showed up on the rooftop, feeling shocked Kei asked why he came there. He answered that he had made a promise, that he would save her should anything happen. Kiyotaka revealed himself to Ryuuen, saying that he came to take Kei back with him. When Ryuuen threatened to reveal his existence and also Kei's secret, Kei interrupted them by saying that it was fine, if they knew about Kiyotaka then they could also reveal her secret as well. She looked at Kiyotaka and he immediately averted his eyes. Ryuuen grabbed Kei's bangs and said that her role was over. Ryuuen ordered Ishizaki to give Kiyotaka a thorough beating, but as Ishizaki approached Kiyotaka, Kei's scream stopped him. She tried to get back up and jump onto Ryuuen. But Kiyotaka assured her that she didn't have to worry as he caught the fist Ishizaki had swung at him. As Kei watched Kiyotaka defeat Ryuuen and others, she was left unable to speak a word.

After the fight ended, Kiyotaka approached Kei and extended his hand, asking why she didn't sell him out to Ryuuen. Kei answered that it was for her own sake while trembling before collapsing into his chest. She admitted that she was scared. Kiyotaka told her that there's no need to think about anything right now, as of this moment, she managed to recreate the present by overcoming her past. He confessed that he was the one who hurt her and wouldn't ask to forgive him, but he just wanted Kei to remember that if something like that happened again, he would definitely save her.}}

Abilities
Kei was assessed as being subpar by the school whose absences and grades in middle school were direct reasons for her being placed in D-Class. She doesn't like academics nor sports, but she is surprisingly able to compete with others and

According to both Kiyotaka Ayanokōji and Kakeru Ryūen, Kei has immense mental strength.

Quotes

 * (Monologue) "The arrow of love I had let loose. If it hits, it's a magical arrow that will cause one to fall in love. This one arrow, one way or another I'll make sure to hit Kiyotaka with it."
 * (Monologue) "Jeez ... inside my heart, there was another me who was squealing while running around. There's no more mistaking it. I just have to admit it now. Seriously, seriously, seriously, my heart's seriously been stolen away. The arrow which had pierced my heart. The arrow of love which I could no longer take out. Is this even possible? Is it even fine for me to fall in love with someone who's been partly bullying me? But it's already too late. The power of this arrow is tremendous. I have, I have towards Kiyotaka-really, seriously, I've fallen in love with him.

Etymology

 * The name Kei means "favor, benefit" (恵).
 * Kei's surname Karuizawa means "light" (軽) (karu), "well, mine shaft, pit" (井) (i) and "marsh" (沢) (sawa/zawa).

Trivia

 * As D-Class is for those with defective traits, Kei's defect is her low grades and for previous absences during middle school.
 * Kei ranks #8 in the "Female Character" category in the 2019 edition of 's  guidebook.
 * In the 2020 and 2021 edition, she is ranked #1.


 * For the 2nd Year arc, When asked about her aspirations for the next year, she answered  'To spend as much time as possible with the person I love. And... to become even just a bit more useful to him. That sorta thing?'