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.
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.
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.
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.
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.
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.
Go-Getter Girl: Very much so, 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.
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.
Oblivious to Love: Oh, so much. You can't stop thinking about him, you say? He's always been there for you? And you mentioned spacing out at the thought of your next session? *beat* You don't read much fiction, do you? Look below, she doesn't.
Parental Abandonment: Her father is divorced and never mentioned and her mother's almost never home, leading to one or two issues.
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.
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.
Voiced by: Kimiko Saito
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.
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.
Voiced by: Ryuta Amazume
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.
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.
Lustful 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.
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.
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.
A 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.
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.
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.]]
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.
Divorced from Nana's mother when she was six.
Lazy Bum/NEET: Doesn't have a job, and doesn't seem able to keep a job.
Nana to Kaoru: Black label Characters
Kaoru'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.
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"...
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.