KAITO, Meiko, Rin, Len, Luka

In the School SEKAI, he joins the VIRTUAL SINGER'S band on the guitar. He is very shy and thus tends to "speak" through his guitar; sometimes hiding from the other characters to avoid talking to them.[citation needed] KAITO appears as part of the SEKAI in the A Bright Future!! event story.

Like all the Virtual Singers, KAITO wears a school uniform which consists of a black blazer with a white border, black pants, a white button-up shirt and a magenta tie. A navy blue checkered pattern is seen on the lapel, cuffs and either side of his pant. On the right lapel, he wears three gold star pins and on the cuffs, there is a small black belt with gold buttons attached to the edge. Under the blazer, he wears a black sweater and is left open. A triangular white and black checkered pattern belt seems to be twice as long since it loops on and under the white skirt. It also hangs loosely on the left side. Under the shirt, an ocean blue checkered cloth covers the right side of the hip and is tied to the left hip. On it, he wears a silver star chain that is also lined with cloth. He wears blue framed glasses in his right breast pocket.

Hatsune Miku: Friend and fellow Virtual Singer. KAITO enjoys singing on the same stage as Miku and loves how Miku shows her appreciation, which can bring him to tears talking about it. Miku can't resist asking for his help sometimes due to how nice he is to her, and wants him to rely on her more.

In the School SEKAI, Miku initially teased him for his shyness upon his arrival, but has seemingly eased up on him by the the event That day, the Sky was Far Away. During his 2022 Birthday Celebration, Miku was the one who coaxed KAITO out of his hiding place so that he could attend his party with the members of Leo/need. They enjoy playing together, and KAITO is able to recognise her love for the members of Leo/need, especially Ichika, which is often their point of interest while talking.

In the Stage SEKAI, Miku appears to respect KAITO a lot, calling him a genius, as she has occasionally sought out his advice. KAITO is happy to help her out, having the perfect knowledge on what would look good on her and what would be good for her shows, whether solo or as a team with someone. He also praises her for her drawings of potential costumes.

In the Street SEKAI, Miku has gotten used to KAITO's carefree tendencies, as when questioned by Akito on if KAITO is always "like that", Miku responds with "like what?"[citation needed] Compared to the other VIRTUAL SINGERS, Miku is also less likely to get exasperated with KAITO for his behavior, and she doesn’t often engage in making jokes at his expense. She also tends to give him taste tests of her and MEIKO's cooking, which KAITO is a fan of, but not when it gets a bit too much.

In the Wonderland SEKAI, KAITO acts as a guiding figure to Miku in addition to being her partner in running their theater troupe. Because of this, the pair appear to be quite close to each other. As well, despite her antics and tendency to involve an often unwilling KAITO in them, Miku appears to respect KAITO and relieves him of his troupe leader duties when he overworks himself.

In the Empty SEKAI, Miku is confused by KAITO and wonders why he's so angry all the time. KAITO criticises her for her thinking Mafuyu is making progress where the progress is way too slow for his standards. They are shown to be on good terms though outside from this, especially after Farewell, My Mask took place, where they worked together to assist Mafuyu who was talking to her mother, both using their harsh truth and comfort to help.

Kagamine Rin: Friend and fellow Virtual Singer. He acts as a doting older brother to Rin and Len and is the VIRTUAL SINGER primarily tasked with keeping them in line. While they often play pranks on him, KAITO doesn't appear to hold grudges, as his Christmas home screen lines reveal that he leaves them Christmas presents every year. KAITO promises that Rin's smile will always stay bright with everyone's help and admires Rin's ability to give joy to any room, also thinking her shows are amazing. Rin appreciates how KAITO listens to whatever she has to say, and is up to helping him with any pranks he wants to pull. Though she tries to reduce demanding things in the future.

In the School SEKAI, Rin looks up to KAITO, often coming up to him with Len for his opinions about things and refers to him as "Big Brother KAITO". However, she gets irritated with his shyness when it prevents him from being able to confidently introduce himself to the members of Leo/need. KAITO will occasionally scold Rin for being too excitable or fighting with Len. He also compliments her when it comes to making things fun, such as videos.

In the Stage SEKAI, Rin respects him, similar to Miku, calling his ideas amazing and his preparations neat. KAITO things she is a wonderful idol alongside the others and enjoys helping out their shows, making sure to point out anything faulty, though fixing it as soon as he can. They both feel the same way about MORE MORE JUMP!'s shows, feeling astonished by them.

In the Street SEKAI, KAITO mentors Rin in DJing, alongside Len. She gets annoyed at his laidback demeanor while he insists he is serious when working with her. Though when he admits to Kohane he takes her more seriously than teaching the others, Rin goes to shake him out of annoyance. They often have differing opinions on things and thus argue a lot, but can be a good duo when needed, such as when helping Kohane with her sampling. She gets confused when he talks about music but thinks when he's explaining things, he sounds amazing, but thinks he should try something new.

In the Wonderland SEKAI, Rin looks up to KAITO at troupe leader, and being able to juggle all the things he has to do, saying she wants to try it out too. KAITO offers to think of performances she can do as a troupe leader, and tells her she doesn't have to be responsible for everything or act like everything is fine, and works better when she's having fun rather than taking everything seriously.

In the Empty SEKAI, Rin thinks he says whatever he wants too much and doesn't let Mafuyu do what she wants in her own SEKAI. KAITO thinks she along with everyone else is soft on her and it won't help Mafuyu reach what she needs. Rin also shows shock when KAITO leaves her and Miku a pillow without saying a word when they fell asleep while playing, showing she'd never seen his nice side that much before.

Kagamine Len: Friend and fellow Virtual Singer. Similarly, to his dynamic with Rin, he acts as a doting brotherly figure to Len, and the two appear to be close. All of their Kizuna Rank titles reference the fact that they're the only male VIRTUAL SINGERS. KAITO enjoys Len's pranks after they've already startled him, and hopes that he can do the same to him for once. Len enjoys KAITO being willing to hang out whenever Len desires and wants to do more and more with him in the future, but promises to not be too demanding.

In the School SEKAI, KAITO appears to be closer with Len than he is the other VIRTUAL SINGERS, and the two are often seen hanging out together following Len’s debut in the SEKAI. Len has also frequently invited KAITO to do things with him, albeit in a less forceful way than the other VIRTUAL SINGERS have tried to include him. Similar to Rin, Len often goes up to KAITO asking about his opinions on things, sometimes on CD choices, sometimes when he disagrees with Rin. KAITO doesn't mind it, as he's used to it by now, and tries to reassure Len on things that are worrying him.

In the Stage SEKAI, Len and KAITO occasionally perform together.[2] When they're not, Len comes up to KAITO for advice, much like the other Stage SEKAI VIRTUAL SINGERS do, which KAITO is organised with, having some of Len's things already set up in order for helping him to be easier. They are able to sow loose threads on costumes back together, which Len learnt from KAITO. Len has also offered to help KAITO after noticing that he’s always working hard by himself.

In the Street SEKAI, KAITO mentors Len in DJing, alongside Rin. Due to his tendency to slack off from teaching them, Len often gets frustrated with him, once threatening to go off to see Akito instead, though KAITO apologised and promised to be more serious. Compared to other SEKAI, Len is more reluctant to show his respect for KAITO due to this offputtingly easygoing nature. When he is a good mentor, Len and Rin get excited from getting praised by him. KAITO also thinks Len is somewhat easy to guess in instances such as Rock Paper Scissors. Though he is happy to help Len in instances such as White Day, which Len is grateful for and makes him a thank you present. And an internal dialogue from KAITO reveals that he’s confident in him and Rin's ability to grow as DJs without his help.

In the Wonderland SEKAI, Len sees KAITO as a sort of mentor figure, asking for his help to do scenes such as stage sword fighting and asking if he's doing well with his performances. KAITO thinks he's getting along with acting great and doesn't like to ruin his fun, refraining from saying things that may risk that.

In the Empty SEKAI, Len thinks his words put Mafuyu in pain, where KAITO thinks that he's too scared and only coddles Mafuyu and doesn't allow her to move forward. Len also gets confused by KAITO's habit to say what he wants to say and nothing else, thinking these words are scary. Though he is able to muster up the courage to stop KAITO in his tracks.[3]

Megurine Luka: Friend and fellow Virtual Singer. The two are noted for being the most level-headed of the VIRTUAL SINGER group, with this being reflected in their Kizuna Rank titles. Luka thinks his presence being able to stop fights is amazing, and puts it on him being caring and kind, thinking he has a wonderful quality. KAITO thinks she has a talent for creating an atmosphere for each song she performs, and looks forward to whenever they do their performances together.

In the School SEKAI, Luka is able to read KAITO's feelings, alongside MEIKO, and tries to get him out of his comfort zone sometimes, such as forcing him out a classroom he was hiding in. KAITO feels awkward when discussing things akin to this but doesn't seem to mind too much and is ok to play for Luka when asked.

In the Stage SEKAI, Luka notices that KAITO takes on so many jobs that he doesn’t leave much time for himself to perform or have general freetime, so she offers to assist him whenever he needs it whether it be with bridging or stage equipment. KAITO calls her thoughtful in this way, and comments on her ways to excite the audience.

In the Street SEKAI, KAITO and Luka have very similar personalities, as they're both carefree on the surface, try to make whatever they teach fun learning experiences, but secretly smarter than they let on. They can talk for long periods of time about silly and peculiar things. Despite their similarities, Luka will occasionally hypocritically tease KAITO for being a slacker.

In the Wonderland SEKAI, Luka feels like she owes KAITO sometimes for him always having to wake her up. In this manner, KAITO is more lenient than MEIKO, letting her sleep for longer before their rehearsals start.

In the Empty SEKAI, despite KAITO being the more brash one of the SEKAI, even he cannot put up with Luka's tendency to be irritating to others and gives up on arguing with her when he can't think of anything to say, which she herself finds amusing.

MEIKO: Friend and fellow Virtual Singer. They are very close, reflecting their statuses as some of the first Vocaloids made by Crypton Future Media, as well as counterpart vocals. Despite this, MEIKO has occasionally helped Rin and Len play pranks on him. His kindness has been a big source of support for MEIKO, and wants to him and Rin with pranks. Doing shows with MEIKO also makes KAITO very happy, and sees her cheerfulness and thoughtfulness, hoping she'll keep being wonderful.

In the School SEKAI, MEIKO was the only one who didn’t tease KAITO about his shyness when he introduced himself to Leo/need, excluding Len, who had not arrived at the time. While not as close as in other SEKAI, the two are on good terms, with MEIKO occasionally inviting along to hang out with the other VIRTUAL SINGERS. Following Len’s introduction, she reminds KAITO that not all of the Kagamine’s bickering is negative, as they are sometimes having innocent fun with each other when they get into passionate debates about things.[4]

In the Stage SEKAI, MEIKO does not use honorifics when referring to KAITO, despite him referring to her as "MEIKO-san", hinting that the two are close. According to KAITO’s A Reliable Senior side story, MEIKO may be a little put off by KAITO’s excitable personality when it comes to his passion for idols and urges him to keep calm, as he’s the only one who could calm the similarly emotional Miku and Rin.

In the Street SEKAI, MEIKO is initially annoyed at KAITO for his shenanigans and would scold him for his behavior. However, by THE POWER OF UNITY, she has grown to trust KAITO more, as proven by MEIKO leaving her shop in his care while she’s away, though she still does not hesitate to tell him to quit it. KAITO enjoys all the cooking MEIKO makes and bases some of their discussions around items on the menu, but does sincerely respect and care about her.

In the Wonderland SEKAI, MEIKO serves as a second-in-command to KAITO as a showrunner, as she often helps him come up with ideas for new stages and assists him in creating them as of On This Holy Night, I Sing. She urges him not to overwork himself but also teases him for it when she finds him in the aftermath of it, though in addition gets told off by KAITO whenever she tries one of her dangerous stunts.

In the Empty SEKAI, they don't interact much, but have the similarity of staying more distant from the others, and share the same irritation of Luka. MEIKO advises KAITO to ignore her, showing they have at least a neutral relationship. In addition, MEIKO is the only one KAITO does not berate about how she treats the members of Nightcord, understanding her opinion, but not how she acts on it. MEIKO also understands his opinion on them and the SEKAI's atmosphere, but not his actions on expressing this.

Hoshino Ichika: A member of Leo/need. KAITO and Ichika bonded immediately due to their similar personalities and love of music. In A Bright Future!!, KAITO reassures Ichika that she doesn't have to be shy about the music she writes.

Hinomori Shiho: A member of Leo/need. After the event story That day, the Sky was Far Away the two become closer due to their similarly introverted personalities and love of music. One of their Kizuna Rank titles is "I'm glad I met you".

Hanasato Minori: A member of MORE MORE JUMP! Minori respects KAITO's role as her stand-in manager and appears to look up to him. The two of them have being big fans of idols despite being idols themselves in common, even down to getting emotional when they watch idols perform.

Azusawa Kohane: A member of Vivid BAD SQUAD. In Walk on and on KAITO watches over Kohane’s track making process and mentors her on sampling, with Rin accompanying him due to KAITO also being her mentor.

Shinonome Akito: A member of Vivid BAD SQUAD. In STRAY BAD DOG it was implied that Akito initially disliked KAITO for his carefree tendencies, however these negative feelings weren’t reciprocated. KAITO and Akito share a few traits in common, such as their love for sweets, desire to be respected, and their outward personalities hiding another aspect of themselves.

Aoyagi Toya: A member of Vivid BAD SQUAD. While he’s often regarded as a slacker by the others, Toya respects KAITO and says that he has a lot to learn from him. They share a number of things in common, such as their love for coffee, their air-headed tendencies, and their ability to excel at things that they like doing.

Otori Emu: A member of Wonderlands x Showtime. She looks up to KAITO as an older brother figure, and aptly refers to him as "Big brother KAITO".