Ouran High School Host Club Wiki

Kaoru Hitachiin (常陸院 馨 Hitachiin Kaoru) is the younger of the Hitachiin twins and is in Class 1-A with his identical twin Hikaru Hitachiin and fellow Ouran Host Club member, Haruhi Fujioka. Despite being younger than Hikaru, he is shown to be more mature and level-headed.


Kaoru Hitachiin is the younger of the Hitachiin identical twins. He and his older twin, Hikaru, are introduced when Haruhi stumbles upon the Host Club. Being in the same class as she is, they are rivals against Tamaki Suoh for Haruhi's romantic attention. Kaoru is just as playful as his identical brother, but is a more insightful and easy-going person. He is also the first of the two to understand that their co-dependence must end if they are to develop into separate and whole individuals.


As members of the Host Club, Kaoru and Hikaru are the "Little Devil" types, as they are mischievous (though not malevolent) troublemakers. They are famous for their "Forbidden Brotherly Love" package, carrying out twin-cestuous schticks for the entertainment of their female customers. A favorite game of theirs is the "Which One Is Hikaru? Game," in which they cover their hair with matching caps and ask people to identify Hikaru. No one except for Haruhi has guessed correctly, with logical reasons for doing so. Due to this, and the fact that she sees them as unique individuals, both brothers develop romantic feelings for her. Though each brother takes her on a date, only Hikaru's is shown in Ep 16 - Operation Haruhi and Hikaru's First Date!

Kaoru and Hikaru are both wealthy and playful; however, Kaoru is the calmer and more mature of the two. When apart from his elder brother, Kaoru becomes a pleasant person, acting in a selfless and serious manner, but when he is with his elder twin, he reverts to being a scamp-like individual. Although the twins have spent the majority of their lives interacting only with one another, Kaoru demonstrates an understanding about social interactions and innate self-control.

Kaoru is born under the star-sign of Gemini, the Twins. The positive traits of this sign are adaptability, versatility, enthusiasm, eloquence, wit and intellectualism; the negative traits being inconsistency, superficiality, indecisiveness, lack of focus and nervousness. There is speculation about whether Hikaru and Kaoru each possess all traits or if the traits are split between them to create a "good" twin and an "evil" twin.

Both of the twins refer to Tamaki as "Boss" in the English version and as "Sir" in the Japanese version.



When not in uniform, Kaoru likes to wear somewhat outlandish designer clothing, but fortunately, almost always wears clothes of different style or different color than his twin, Hikaru. In the manga, he has short, somewhat messy auburn hair. Kaoru has also dyed his hair powder blue, and later pink, to confuse the Host Club and their guests, although Haruhi still manages to tell the Hitachiin twins apart.

Kaoru's orange rose.

When facing them, Kaoru's parts his hair to the left side, while Hikaru's parts his to the right; when they stand together Kaoru is usually on the left with Hikaru on the right. Although they tell Tamaki that they switch it on a daily basis, the parting of their hair is generally consistent, unless they are deliberately attempting to confuse others. Both twins possess amber-colored eyes, a thin face and pale skin. After graduating and becoming a college student, Kaoru grows his hair longer than his twin, who maintains the same short hairstyle.

Kaoru's rose color in the Host Club is orange. In Japanese culture, this signifies happiness, matching him quite well as his nature is more optimistic when compared to Hikaru's. In Western culture, an orange (or coral) rose is symbolic of romantic energy and enthusiasm; Kaoru displays this in his eagerness to devote himself to his brother, his friends and the Host Club's clients.


As children, Hikaru and Kaoru are inseparable and dislike everyone with the exception of their personal maid, whom they adore. The cunning woman promises to play the "Which One is Hikaru? Game" with them until she gets it right because the twin toddlers say they will give her the combination to a safe when she wins. During the night, the alarm sounds and the twins discover their playmate heading down a ladder with the family's riches. She has broken open their piggy bank to access the slip on which the combination is written and broken her promise to them, as well. Disappointed, they ask why. She replies that she simply can not tell them apart and perhaps no one ever will, insinuating that only people who can properly identify them as being trustworthy. This comment becomes a self-fulfilling mantra for them, keeping them isolated and stunted in social skills.


Because of their long-standing co-dependency, the twins fail to develop social skills with others. During grade school, they refuse to interact with anyone unless they can tell the two apart; however, no one can. Their pain is kept inside, furthering their isolation and perverting their psyches until Tamaki Suoh invites them to join the Host Club. Though uninterested, they ask him to play their who-is-who game to amuse themselves. Tamaki accepts on the condition that if he wins, they must join his club. Though he initially loses and is ridiculed by the twins who have discovered that he is the illegitimate son of Ouran's Chairman of the Board, Tamaki continues until he gets it correct. His reasoning is intuition which they refute, but his persistence and his willingness to accept them as they are, their faults as well as their assets, impresses them as nothing had since the day their maid declared others' inability to tell them apart a measure of a person's worth, and they join the Host Club.

Due to his constant monitoring of Hikaru's emotions, Kaoru becomes adept at figuring people out. An example of this occurs during Ep 15 - The Refreshing Battle in Kuriazawa!, when Hikaru becomes jealous of Haruhi's childhood friend, Arai, and lashes out at the unoffending male before fleeing. It is Kaoru who helps his brother understand his error and who apologizes to Arai (dressed as Hikaru) before explaining to the Hosts, in depth, what makes his brother so difficult. He is also the one who sets up Hikaru's date with Haruhi (despite his own budding feelings for her), as he understands his brother's underlying romantic feelings for Haruhi and believes that she can help him learn how to be more considerate of others.


The Hitachiin Family

The Hitachiin family cannot be described as a cohesive family unit, as they do not spend much time together. Both Hikaru and Kaoru often mention that their parents work a lot and, as a result, cannot be there for them. This leads them to rely and depend only each other, hence their somewhat self-isolating tendencies.

Hikaru Hitachiin


Hitachiin twins and the more outrageous of the two, Hikaru depends on Kaoru to help him understand himself and others better. Although both he and Kaoru truly care for and respect Haruhi (as she was the first one to truly enter their world), they "lose" her to Tamaki. Despite his frequent innuendos and teasing, Hikaru has been shown to be very protective of his younger brother.

Hikaru is undoubtedly Kaoru's closest life-long friend and companion. Despite being the Identical Twins he is boisterous and somewhat selfish, to the point that he is extremely dependent on his brother to help him manage his feelings; thus, his social skills and emotional control remain undeveloped. In both the anime and the manga, they begin as two halves of a unified whole, symbolized by a plant with two entwined leaves hatching from one egg, but as the series continues, they develop their unique personalities and become individuals in their own right, symbolized by flowers of differing colors sprouting from their respective plants.

Yuzuha Hitachiin


Kaoru's mother, Yuzuha Hitachiin, is a famous fashion designer of her own company. Kaoru's savvy fashion sense, appearance and personality come from his mother (though he and Hikaru once jokingly mentioned that they fear for their future, due to their inherited shyness from their father). A running gag in the manga is the fact that Yuzuha constantly confuses them. Tired of correcting her, the twins allow her to call them by either name, even though it is later revealed that she actually can tell them apart, but pretends not to for her own amusement.

Hayato Hitachiin


Kaoru and Hikaru's father, whose name is unknown but who adopts his famous wife's surname, runs a computer software company. He appears to be a more down-to-earth person than his spouse and sons and is often hidden in the shadows, appearing invisible to everyone else around him (including his family); at one point, Haruhi even mistakes him for Yuzuha's escort. The Hitachiin patriarch is also noted to be one of the few people who can consistently tell the twins apart, even if their backs are turned to him. Although he does not show his emotions easily, it is evident that he cares much more for his children than he lets on and gives good advice when necessary.

Kazuha Hitachiin


Kazuha Hitachiin is Kaoru and Hikaru's grandmother. She is known to be a free-spirit and well-known floral designer who decorates her hair peculiarly with flowers, earning the twins' ridicule. It is later revealed that the twins made up the hairstyle as a prank when they were toddlers. As children, Kaoru and his twin would draw their own floral designs, but upon learning that their grandmother wanted to use the designs on bath tissue, they decide that she is a witch who is incapable of being nice to others. However, eleven years later, she admits that she kept the drawing and that the twins have great talent. She is noted to travel frequently and rides a motorcycle.

Ageha Hitachiin


The little-seen younger sister of the twins, Ageha is a manga-only character. Although the twins dote on her and give her dresses and toys, she is unimpressed by them and frankly rejects their presents to their faces.


Before the Hitachiin twins join the Host Club, both Kaoru and his elder brother are socially awkward and inseparable, but gradually, they begin to open up to people. Although their co-dependence is depicted as a strong force in both the manga and anime series, both story lines end up with the twins seeking greater independence for themselves. Kaoru is the one to initiate their independence, but it is Hikaru who validates their efforts by dyeing his hair a darker shade of brown (in the manga) to make it easier for people to tell them apart.

Haruhi Fujioka


As a student in Class 1-A, Haruhi is classmates with the Hitachiin twins. Interestingly enough, she is also one of the few people who is able to easily tell Hikaru and Kaoru apart. She is undaunted by their teasing and either tolerates or chides them on their sometimes manipulative behaviors, thus acting as a good friend to both. Kaoru initially looks down on Haruhi, but later changes his mind and develops romantic feelings for her. After an argument with Hikaru, Kaoru takes Haruhi out on a date to an amusement park in Chapter 52 of the manga, in which he confesses his affection for her and kisses her cheek; however, since he values his brother's familial relationship more than a potential romantic relationship with Haruhi, he tells her that he will be giving up so Hikaru might have a greater chance of winning her heart.

Tamaki Suoh


Tamaki is one of the first people to actively seek to break through the isolation that he sees in the twins by inviting them to join his newly formed Host Club. Although both Hitachiins initially find him annoying and troublesome, they eventually grow to admire Tamaki because of his ability to simultaneously see them as unique individuals and as an inseparable unit, which he views as a positive aspect of their relationship. In the manga, Kaoru frequently plays jokes on Tamaki and finds it especially amusing to tease Tamaki over his desire to be called "King" (aka "Tono," "Milord," or "Boss") and, instead, calls him an idiot; the anime differing by expressing the twins' use of Tamaki's preferred title over other names. Knowing that Tamaki loves Haruhi, even if he is oblivious to it, Kaoru and his brother flirt with her endlessly to either prod him into reality, or just to get him fired up for their amusement. An example of this is in Ep 07 - Jungle Pool SOS!, where they antagonize him into a water fight by stating their intention to marry Haruhi and go off on a honeymoon. It should be noted that, despite being frequently exasperated by their antics and calling them the "shady twins," Tamaki genuinely seeks their welfare.

Kyoya Ootori


Kyoya and Kaoru are seen to get along and understand one another rather well, each being the more mature half in their "paired" relationships (Tamaki and Hikaru, respectively). Kyoya also turns to Kaoru whenever he needs help requiring intelligent thought and research, indicating his respect for Kaoru's unique strengths. This is seen in the manga during the sports festival, when Kaoru becomes White Team Captain Kyoya's right-hand man, investigating and reporting on the Red Team's abilities and thus helping Kyoya select the best White Team candidates to confront them. In addition, in the manga chapters revolving around finding Tamaki's mother, Kaoru and Kyoya join forces to gather information, keeping it secret from everyone else in the Host Club. Kyoya demonstrates his trust in Kaoru during these times, as he is able to express his own normally shuttered feelings about the situation since he knows that Kaoru will keep his confidence, even from Hikaru.

Mitsukuni "Honey" Haninozuka


As the eldest host, Honey is both admired and respected by Kaoru for his intelligence and wisdom despite his loli-shota image; in return, the shorter boy recognizes the positive influence Haruhi exudes over the twins. Although the two do not interact much in the anime, the manga shows that Kaoru usually confides in the other whenever he has issues concerning his elder brother or his love interest or both. He is always given sound advice, and is treated with sincere concern, since Honey belives that Kaoru's heart may have broken over "losing" Haruhi.

Takashi "Mori" Morinozuka


Like the way Honey mentors Kaoru, Mori serves as a mentor to Hikaru. Being a compassionate and highly observant person, he understands the problem of the twins' similar feelings for Haruhi from each boy's perspective, and since he knows that Honey assists Kaoru, Mori avails himself to Hikaru for solace and much needed time away from Kaoru. Kaoru recognizes Mori's enormous contribution to Hikaru's personal growth and thus respects his opinions on any given situation. It should be noted that they are also alike in their quieter and more thoughtful natures when compared to their other half (Honey and Hikaru, respectively).

Kazukiyo Soga


Kazukiyo Soga is the Class Representative for Class 1A. He is the only other megane character in Ouran, though very different from Kyoya. He is best known for his antics in Ep 21 - Until the Day It Becomes a Pumpkin!, wherein Class 1A prepares a Halloween frightfest and the twins overhear that Kazukiyo is a scaredy cat. They band with him and Haruhi as Team B, pranking him relentlessly until they see what they think is the Clocktower Witch. Kaoru and Kazukiyo end up locked in a room together where Kaoru is surprisingly friendly to Kazukiyo in the absence of his brother and Kaoru reveals that they had plans to make Kazukiyo appear brave and manly in front of his crush, Momoka. In Volume 13 of the manga, Kazukiyo and Kaoru share a room together during the class ski trip, and Hikaru ends up joining them on the second night when rooming with Haruhi becomes too awkward. He is later seen at the Hitachiins' New Year's Eve party, assuring a group of girls that his leg is healing fine. When Haruhi announces in Chapter 83 of the manga that she is leaving to study abroad for a year, Kazukiyo panics that the twins' pranks on him will increase without her mitigating influence. When Kazukiyo admits his feelings to Momoka in college, Haruhi and the twins are shown in the background cheering him on.

Mei Yasumura


Mei is an aspiring designer and a huge fan of the twins' fashion designer mother, Yazuha. After accompanying Haruhi to the Hitachiin mansion and meeting Yuzuha, Mei gushes that she is the "perfect" woman. Not yet used to their personalities, she falls for several of Yuzuha's and the twins' pranks. Being the first person to realize Haruhi's feelings for Tamaki, she is also the one to bring it to Hikaru's attention, causing him to become intensely jealous of Tamaki, even though Hikaru is still oblivious to his own romantic feelings for Haruhi. Before she can help Haruhi understand her confusing feelings for Tamaki, Kaoru calls Mei's cell and urges her to stop so as not to give Tamaki an advantage over Hikaru. The twins get along well with her. They also invite her to the New Year's party at their mansion, where Kaoru expresses his concerns to her about Hikaru's confession to Haruhi. Mei also tells Haruhi that while it was rude of her to not notice Hikaru's feelings, it would be even worse to date him out of pity. When Mei is studying fashion in college, the twins agree to be models for her fashion show, but send Ritsu Kasanoda in their place in a scheme to set the two up on a date.


  • The name Kaoru means "fragrance, fragrant" (馨).
  • Kaoru's surname Hitachiin means "always, ever, endless/endless time, infinity, sempiternity" (常) (hi), "land" (陸) (tachi) and "hospital" (院) (in).


Main article: Kaoru Hitachiin/Image Gallery


  • The manga and anime depict Hikaru and Kaoru's relationship as two plants growing from a single seed. Later, in recognition of their increasing individuation, two huge flowers of identical type bloom in different colors.
  • Kaoru often turns to Honey for advice after an upset with Hikaru, whereas his twin seeks comfort from Mori.
  • The Hitachiin twins share the same birthday as the Kurusu twins (from Uta no Prince-Sama).
  • Like the other Hosts, Kaoru's phone matches his rose color, which is coral pink/orange.
  • Kaoru's seiyuu in the Drama CD's voiced Hikaru in the anime.
  • After Hikaru dyes his hair in the manga, the visible differences between the twins increase. Hikaru starts to wear clothing with bolder patterns while Kaoru opts for more classic outfits and, in the chapter title pages, Hikaru is usually drawn with angry eyebrows and an open mouth while Kaoru maintains a calm smile.
  • Both Kaoru and Hikaru are right-handed.
  • Early in the manga, Kaoru is acknowledged as a "handsome homosexual" by Bisco Hatori; however, she also admits that she changed direction on many things throughout the progress of the series, as shown when Kaoru shows interest in Haruhi.
  • Kaoru is said to be 10% less evil than Hikaru.

Anime Appearances

Chapter Appearances


  1. Hatori, Bisco (2005). "Chapter 4". Ouran High School Host Club, Volume 2. Viz Media. p. 7. ISBN 1-59116-990-9
  2. Chapter 3