A sullen, unattractive slacker who's a childhood friend, next-door neighbour and former rival of Nana, Kaoru has been nursing a crush on her for an unspecified time before the start of the story. He used to be on par with her without trying until middle school, when her hard work and dedication to a goal began to pay off, leaving him struggling to catch up. As a result, he stopped trying and resigned himself to watching and urging Nana on from afar. He discovered BDSM around the same time.
Most of the time, he can be found hanging with his buddies in 2-F. Usually discussing porn. Nicknamed "Creepy-mura" by the rest of the class.
- Ascended Fanboy: Kaoru in Black Label. At first he only pretended to be Sarashina's characters during his breathers with Nana. In this, he ends up one of the characters in Sarashina's books, role-playing alongside and learning directly from said author at that.
- Badass Boast: In chapter 96/74 (It Makes Sense in Context):Kaoru (to Hiroshi): They may have thrown out your porn, your pride, but I'll get it back for you.
- Beady-Eyed Loser
- Brilliant, but Lazy: He has the ability, but little motivation after his rival left him so thoroughly behind. In addition, if you get him onto a subject he is interested in (BDSM), he's downright erudite about it.
- Character Development: His grades begin improving, his health and stamina go through the roof and he shakily makes new friends and gains confidence throughout the course of the story.
- Chivalrous Pervert: He'll push Nana to the edges of her boundaries... but no further.
- Disappeared Dad: His dad died when he was very young and was raised by his mother.
- The Eeyore: Committed to the belief that he's unworthy of Nana, and resigned to his fate as an underachieving loser that'll be left behind once Nana graduates.
- Grumpy Bear: He's not happy about being a romantic lead.
- Hair-Trigger Temper
- Insecure Love Interest: Because of a lot of tropes here, especially the two below... this applies to him. But not so much in Black Label.
- I Don't Want to Ruin Our Friendship: He is absolutely, soul-crushingly terrified of losing Nana, to the point that he completely misses out the increasingly obvious fact that Nana's in love with him.
- I Want My Beloved to Be Happy
- Jerkass: Unpleasant towards everyone, particularly towards his mother...
- Jerk with a Heart of Gold: ...but he does have a huge soft spot for Nana.
- Mr. Exposition: Particularly in matters of BDSM.
- Not So Harmless: He appears as a beady eyed gonk loser... but everyone forgets that up until his massive self esteem failure, he was Nana's scholarly rival. Nana, who is the top of her class and aiming for Toudai.
- The Student council president's sister has to pull the pres. aside and point out just what Nana's coded messages meant — he's not just a loser who is bothering Nana, he's Nana's boyfriend, although neither of them realize it.
- Oblivious to Love: Has no clue about Nana's feelings (Something that he does get better at, with time). To be fair, neither does she - of his or her own.
- Platonic Life-Partners: Sort of has this dynamic with Tachi.
- The Slacker
- Smarter Than You Look: A lot of people are surprised by his seemingly random bouts of intellect and drive. As mentioned in Sunstone, bondage is a smart person's game.
- Took a Level in Badass: By the midpoint of the series, his daily jogging has put him in very good shape — he is able to run several miles around town searching for Nana without breaking a sweat, while the all-round perfect Bishōnen student council president is left out of breath and near collapse.
- Tsundere: Type A (tsuntsun). Kaoru doesn't really associate with anyone else outside of his personal friends in class 2-F, Nana, Tachi and his mentors in Tachibana and Sarashina (eventually; the last four come over the course of the stories), isolates himself to some degree and is rather hostile for most of the day (even to his own mother). That said, Nana is the only subject/person that can pierce his apathy. He cares about her deeply, to the point that he is less and less of a Type A with each passing arc of the story.
- He can even act tsundere towards studying.
- Wholesome Crossdresser: Roped in to play the part of a short, ugly girl in the school play.
- You Are Better Than You Think You Are:
Gorgeous, top student, athlete, hardworking vice-president of the student council - Nana is near the top of the heap in school. She drifted apart from her childhood friend Kaoru once she dedicated herself to becoming a lawyer (ironically, his encouragement provided the impetus). She doesn't have much of a life outside of school and studying, though, which is why she finds it difficult to relax and take a break.
Her headstrong and imperious personality meant that Kaoru was likely her only friend until high school (and being assigned to the student council), as she tended to scare people off.
- The Ace: She would be an ace, were it not for the fact that she excels in school only. Her studying doesn't leave much time for anything else. Later we see that she's closer to a Broken Ace, due to the pressure she feels from her mother and classmates.
- It could be argued that BDSM helps her stay sane by stepping out of all her expected roles.
- Attractiveness Isolation: She has a form of it, more or less due to be being something of an iron lady and having sacrificed basic skill for awesome training (details below)
- Beneath the Mask
- The B Grade: The catalyst for the "breathers;" at the start of the manga, Nana is so stressed by all of her responsibilities that she isn't scoring as high as she used to. After she has her first "breather," she scores even higher than she did before and makes her pursue more "breathers" with Kaoru.
- Brains and Bondage
- Break the Haughty: Many of the things Kaoru says during "breathers" go in this direction, especially the spanking session which she agrees to for causing Kaoru to have make up classes during winter break.
- Covert Pervert
- Daddy Issues
- First-Name Basis: With Tachi.
- Go-Getter Girl: Which is why she needs her 'breathers' to relax.
- Green-Eyed Monster: If one notices, any time that she, Tachi and Kaoru are together... she'll tend to get a little clingy to Kaoru. Since she's been having the "breathers" along with Tachi, she will get progressively more jealous about the whole session on a sub-conscious level. It's partly because her feelings for Karou also make her selfishly protective of his attention and praise. Yeah, she is completely clueless about this.
- Hair Decorations: A white ribbon tied in a big bow.
- Heterosexual Life-Partners: With Tachi
- Hello, Nurse!: Subverted. All the boys want her, but don't dare to approach because she's an Iron Lady.
- Iron Lady: She's really book smart and is part of the student council, though she commands authority regardless.
- Lethal Chef: She tries, but has no experience in cooking... anything. It leads to 'experimental' concoctions like egg sake with ginger, garlic, tomato and vinegar:Kaoru: Why is it red?
- Little Bit Beastly: Dog-themed in chapter 70.
- Ms. Fanservice
- Not So Different: She has a number of similarities to Kaoru, Tachibana and Her own mother.
- Generation Xerox: Virtually identical to her mother, and she knows it - when we finally meet her father, it reminds her unpleasantly of all the apparent similarities between her parents, and the tense relationship she has with Kaoru.
- I Am Not My Mother: The fact that she has been turning out like her mother doesn't please Nana when she discovers it.
- Parental Abandonment: Her father is divorced and never mentioned and her mother's almost never home, leading to one or two issues.
- Platonic Life-Partners: As of Black Label, she has this dynamic with Tachibana.
- Sacrificed Basic Skill for Awesome Training: What starts the plot, in a way, is this trope at play. She studies to such a degree that she doesn't really know how to relax, unwind, and not be in a position to study. The cause of this is her aspirations in becoming a lawyer.
- Stepford Smiler: Type A - Nana has two very specific smiles, one for keeping up appearances and another that is genuine, which is rare. The reason for this is more complex than one would expect, but it boils down to stress from keeping up her masquerade for her classmates and from acting as go-between for her divorced parents as their relationship continues to fragment. The latter is what eventually guides the plot, and uncovers issues she has with her parents that she has kept to herself since the age of six.
- The Tease
- Tsundere: Type B (deredere). At the start of the manga, this is Nana. A compassionate, devoted individual to almost everyone around her. Save for Kaoru, whose initial hostile manner seem to toss her for a loop and bucks against her own headstrong personality (causing a Type A streak as a reaction). This changes over the course of the mangas - the more that Kaoru opens up to her through the "breathers", the more she (unknowingly, at first) gushes about him to others and grows concerned about his well being.
- "Well Done, Daughter!" Girl: Flashbacks reveal part of the reason she wants to be a lawyer; she wanted to emulate her father. Who later asks her which parent she loves more. Yeesh.
A nurse at a local hospital. While she disapproves of her son's interests and wants him to stop wasting money on porn and sex toys, she takes care of him like a mother would and pesters him to have better manners.
- Gonk: Kaoru takes after his mother, although this was toned down as the manga progressed.
- Parental Abandonment: Isn't nearly as bad as Nana's mother, but has to leave him alone a fair bit.
- Parents as People: She doesn't get her son's interests at all but she does take care of him and she approves of his friendship with Nana.
- Parents Walk In at the Worst Time: Walks in after Kaoru vomits out a drink Nana had made for him and staining her dress. His mother assumes it's blood and proceeds to slap the hell out of him for forcing himself onto Nana until Nana explains "she's at fault", then she just muses at the prospect that they had sex.
The student council president and rival for Nana's affections.
- Break the Haughty: Happens to him after being top of his school in final exams, when his manipulative sister rats him out to his mother on a porn he was watching as a reward to himself, which ends up getting thrown away.
- Character Development: He realizes how much of an ass he was to Kaoru when Kaoru sympathizes with him on his fetishes.
- Covert Pervert: Dude's got a dickgirl fetish.
- Smug Snake
- Wrong Genre Savvy: Thinks Kaoru is a slacker fanboy who is just around Nana because he's her Childhood Friend. He is... but he's also a Jerk with a Heart of Gold and in the middle of a Childhood Friend Romance Upgrade with her.
Yagami KikukoSister of the student council president; she's quite perceptive and can tell almost instantly that Nana and Kaoru share a bond. She isn't above telling her brother what she knows either.
- Gold Digger: Of the familial variety; she uses her brother as a social climbing tool.
- The Man Behind the Man
- Manipulative Bitch / Bitch in Sheep's Clothing: Pushed her brother to become the top of the class and go to Tokyo U. in her stead, simply to use his connections to make friends with the upper class. On top of it all, she dug out his favorite porn video and 'accidentally' watched it with their mother.
- The Matchmaker
- Smug Snake: She's not as bad as her brother, but she still tries to help him win Nana over, despite recognizing almost instantly there's something going on between them.
Doumoto and HoshinoKaoru's fellow friends in Class F - and fellow porn appreciators.
Mitsuko TachibanaLustful and energetic owner of a porn shop. Acts as a mentor and introduction into the deeper world of BDSM for Nana and Kaoru. She's also the personal slave of Kaoru's favourite BDSM author, Sarashina-sensei.
- Brains and Bondage: She's a Tokyo University graduate with a Masters degree in Liberal Arts who also happens to run a porn and fetish gear shop.
- Cannot Spit It Out : In Black label, the closer that we look at Tachibana and Sarashina relationship... the more you begin to notice that Tachibana is hesitant about her affections for Sarashina, as much as Sarashina is a Insecure Love Interest. This is due to the fine line that they have as Slave and Master. It takes the presence of Nana to slowly chip away at this and blur that divide, which is ironic, as Tachibana did the same for Nana and Karou months ago.
- Cool Big Sis
- Genki Girl
- Ms. Exposition: If Karou is not giving a lecture on BDSM matters, he's likely getting one from her. Which is a Chekhov's Gunman that doesn't get solved until Black Label.
- Ms. Fanservice: In Black Label she seems to spend every other chapter at least topless.
- Not So Different: Very similar to Nana in more than one way.
- Platonic Life-Partners: As of black label, with Nana
- Screw the Rules, I'm Beautiful!: Subverted: her assistant at the sex shop asks her to do some work for a change, but when Kaoru comes by to ask about rope she gets sidetracked, the assistant is seen thinking he doesn't mind because he has a crush on Mitsuko.
- Sexy Mentor: To Nana, of all people. She is also this to Karou.
- Where Does She Get All Those Wonderful Toys?: We quickly learn that she gets them from her shop.
Ryoko TachiA student athlete at a nearby girl's school, she first met Nana at a track meet; Nana beat her and she swore to defeat her next time. Through a series of coincidences, she discovered their breathers and demanded to be included in their next BDSM session, to determine whether it was as "healthy" as Nana claimed.
- Ambiguously Brown: Justified: She has a deep tan.
- Bifauxnen: At least 2 people are convinced she's male when she's first introduced, one of them being Kaoru who she's been running with several times before The Reveal.
- Cute Little Fangs: During the "Dog Girl" bondage session, she puts some on among other things.
- Dog Girl: She's enthusiastic at playing one in chapter 70.
- First-Name Basis: With Nana.
- Genki Girl: Very impulsive and full of energy.
- Heterosexual Life-Partners: Seems to be becoming this with Nana.
- Hidden Depths: At part of the reason why she insists on doing the breathers with Nana and Kaoru is because she wants friends, which she doesn't have many of at her school.
- I want my beloved friends to be happy: Notably, while she is Nana's athletic rival, she acknowledges that Kaoru's planet-sized feelings for Nana mean he won't even consider her as an option. If given the choice, she will step aside for Nana. She has also been actively encouraging Nana and Karou towards each other.
- Lonely at the Top: Tachi was able to join the Athletic Team as a freshman due to her skill, but was resented by a whole lot of the club as a result. Since she can't make friends there and spends a lot of time there, she lacks friends.
- Matchmaker Crush: On Kaoru, but she tries her best to get them together and genuinely means it.
- Peek-a-Bangs: Sometimes.
- Platonic Life-Partners: With Kaoru.
- The Rival
- Unknown Rival: When she first talks about their rivalry, Nana is a bit lost about it. After a few "breathers" and some one-on-one time with Kaoru while he is doing maintenance, Tachi seems to be vying for Kaoru's affections a bit... and knows that Nana doesn't have a clue about Kaoru's affections for her. Nor about Tachi's own for him.]]
- She Ties Up Nicely
- She's Got Legs: Seeing as Nana has both the breasts and the backside, the focus is instead on her legs.
- Secret Keeper: For Kaoru; she is the one person that seems to truly understand how devoted he is to Nana. For both, she is also one of the few that knows that they care for each other and are oblivious to it, and well as keeping the "breathers" hidden.
- Tan Lines
- The Tease/The Gadfly Yes, she is both. This is because Tachi is more of a gadfly but every so often she comes off as heavily suggestive when teasing. All non-sexual and usually at Karou's expense.
Nana's MotherA police chief, her job means that she is almost never home. Despite that, she played (and still plays) a large part in shaping Nana's life and psyche.
- Married to the Job: Fully dedicated to her job as police chief to the point that Nana must fend for herself.
- One-Note Cook
- Parental Abandonment: She very rarely comes to visit or take care of Nana on account of her job as police chief.
- She Who Must Not Be Seen: Only ever shown in silhouette in Nana's flashbacks. Until she finally came home.
- Stepford Smiler: She locked herself out emotionally to deal with the chaos of her marriage going up in flames. She wasn't good at it in front of her husband, whom she lashed out at regularly, but it was impressed upon Nana so strongly that she had picked it up as a way of coping with her stress before the "breathers" took over.
- Calling the Old Man Out: It takes Kaoru screaming down the phone at her to finally get her to come home and visit her bedridden daughter.
Nana's FatherDivorced from Nana's mother when she was six.
Nana to Kaoru: Black label Characters
Shuutarou SarashinaKaoru's favourite S&M author takes centre stage in the Black Label spin-off. It's his invitation to his summer home that kickstarts the story.
- Cool Old Guy
- Early-Bird Cameo: Possibly on chapter 27 page 4, when Nana's freaking out before Kaoru spanks her the image on the left looks very similar to him.
- No Celebrities Were Harmed: He looks like Oniroku Dan, a Japanese SM writer.
- Not So Different: Sarashina and Karou seem to be cut from the same cloth. They share many of the same insecurities with their partners, the same worries and have the same considerations. Sarashina is more intense than Karou, which can be summed up to his long relationship with Tachibana but outside of that both are Insecure Love Interests for much of the same reasons. Tachibana refers to them as "Father and Son"...
- Old Master
- Write Who You Know: More or less. The plots and characters to his books are based in part on role-plays between himself and Tachibana. The session that Nana and Karou are taking part in is part of a scene to a new book of his.