Mitsukuni "Honey" Haninozuka is considered a "boy lolita" or "loli-shota;" basically, an older boy who is attractive to girls because he is child-like and cute. Honey, himself, loves cute things and indulges in sweets of cake and candy on a near-constant basis; this, despite being smaller than average for his age and a martial arts champion. He is a perennial optimist with an innocent approach to life that makes him appear to be more like an elementary school student instead of a 3rd-year high school student, as well as the eldest of all the Hosts. He is often seen riding on the shoulders of his best friend and cousin, Takashi "Mori" Morinozuka, and is almost always carrying his pink stuffed rabbit, Usa-chan. When he speaks about positive things, flowers float about his head.
Although he often appears dimwitted, Honey is actually highly intelligent and clever, and is able to see that Tamaki, Hikaru and Kaoru all have feelings for Haruhi. Despite his generally positive nature, he angers easily when awakened from slumber and since his bloodtype is AB, most of the hosts believe that he has a split personality (i.e. Dark/Nice Honey). As the oldest person in the club, Honey refers to his fellow hosts using the "-chan" honorific. He also serves as a mentor-figure for the hosts, especially Kaoru, and is eager to help others find their identity, just as Tamaki helped him find the courage to be his own true self. However, he does not believe in babying people, even Mori, and typically does not offer his advice unless he is approached first. He is adoring of his stuffed bunny, Usa-chan, as it was made just for him by his late grandmother, and he harbors an insatiable appetite for sweets and cake, admitting that he eats three whole cakes for dessert every evening after dinner.
Honey is born under the star sign of Pisces, the Fishes. The positive traits of this sign are imagination, kindness, compassion, intuition, sensitivity and selflessness; the negative traits being escapism, idealism, a weak will, over-sensitivity, pessimism and indolence. Since he is born on the 29th of February, leap-day, Honey is considered a "leapling" and only celebrates his actual birthday once every four years, giving these qualities a lesser influence on his personality.
Honey posesses a babyish face and is short in height; his actual height is 148cm (4'11") but he grows to be 180cm (6') in a 2011 omake in Haruhi's dream. His hair is short and honey-blond in color (as opposed to Tamaki, whose hair is pale blond). When not in Ouran's school uniform, he tends to dress simply in the anime but outrageously in the manga. He is typically seen with his cousin Mori or his stuffed bunny Usa-Chan (aka Bun-Bun) by his side, and whenever he speaks, flowers float around his head; the only exceptions being when he is angry, upset or confused.
Honey's rose color in the Host Club is pink. In Japanese culture, this signifies joy and trustworthiness; Honey possesses both of these traits. In Western culture, the pink rose is a symbol of nurturing and affection; also traits which Honey demonstrates throughout the series.
The Haninozuka family have excelled in martial arts for generations, to the point that all family members are martial arts champions. Upon greeting, it is tradition for family members to fight as a reminder to keep their guard up. It should be noted that height is not significant in the Haninozuka Martial Arts, as it is mentioned that, "There are more small people in the [Haninozuka] family than not." Honey is said to be the best martial arts champion in Japan, his prowess such that he has been instructed to never go all-out in a public fight. The reason given by Tamaki in Ep 18 - Chika's "Down with Honey" Declaration! is that if he ever fought all-out, he would be viewed as a secret weapon and thus, would risk Japan's good relations with the United States.
Yasuchika Haninozuka, affectionately nicknamed "Chika" in the anime, is Honey's younger brother and appears to be his polar opposite. In contrast to his elder brother, he is taller and has great loathing for sweets, cute things, and his sibling's love for them. When Chika openly accuses his brother of being an alien who uses Usa-chan to communicate with a "mother ship," he explains that this accusation stems from the fact that Honey eats three cakes for dessert every night and holds a weekly eat-all-you-want midnight cakefest, which confounds his brother as Mitsukuni never seems to gain weight. Over time, Chika is revealed to actually care deeply for his elder brother and holds great respect for his martial arts skills, though he still remains frustrated by his brother's loli-shota tendencies.
Mori and Honey are not only cousins, but best friends, whose close relationship is rivalled only by the Hitachiin twins. Honey is the only one who calls Mori by his first name instead of his nickname and vice versa. Many generations before marriage united their families, the Morinozuka household served the Haninozuka household; and so despite the marriage, the two continue to be a team. Mori is very protective of and loyal to Honey, and Honey genuinely likes and appreciates Mori; he can be seen riding on his shoulders frequently, interacting with him constantly, and even ruffling his hair once in a while. They depend on each other as brothers do, Mori serving as confidant and companion in place of Honey's natural brother who wants no part of him.
Throughout the series, it's evident that Honey's feelings towards Haruhi are tender, but merely platonic. He finds her to be another cute thing, like his stuffed rabbit, Usa-chan; and he is the first person to be friendly towards her when she first entcounters the Host Club, calling her "Haru-Chan" and inviting her to eat cake with him. He is also the second person (after Kyoya) to realize Haruhi's true gender. His relationship with her is best described as a brother/sister-like one, as he can often be found helping Haruhi out in various scenarios, especially when it comes to understanding her own or other's feelings.
Honey likes and cares about Tamaki very much, seeing as how when Tamaki first invited him to join the Host Club, he was the one to say that it was okay to like cute things and to eat cake if that is what he likes. The loli-boy, who had been wanting to embrace that part of himself for quite a while, is thankful and touched by Tamaki's acceptance of his true self, much like Mori does. Honey is also the first to defend Tamaki against the Newpaper Club when they attempt to discredit Tamaki, believing that he's wielding his family's power over the rest of the Hosts. Honey says (paraphrasing), "Tama-chan would never do that. We all like Tamaki. That's why we're in the Host Club in the first place."
Honey has a mutual relationship with the twins. When on the subject of Honey, they often comment about his loli-shota ways. The three have known each other since childhood (after all, since they're all on the same status level, classmates don't change very often) and the twins are the ones who tell Haruhi about Honey's past (eg. his skills, how he gave up his loli-shota ways for a time being, etc.) Often, they view Honey as a kid, but are still fearful and respectful of him, as demonstrated when the twins and Tamaki both cower in fear at Honey's bad temper upon waking up and finding his bunny dirty. They also address Honey respectfully, using "senpai", as he is their upperclasman. Overall, the relationship between the three of them is quite friendly, and they acknowledge each other with respect.
Reiko Kanazuki is a manga-only character who develops romantic intentions towards Honey. They meet when she trips over Usa-chan and Honey offers his hand to help her up, thus displaying the first nice action any human being has done for her in a long time. As a member of the Black Magic Club, she becomes obsessed with casting spells to "capture his soul" since she believes that he's captured hers, and despite the loli-shota's initial misgivings, he realizes that her actions are attempts at communication. Honey explains that an easier way to "capture another's soul" is simply to talk to them and learn about them. When Kanazuki begins to attend the Host Club, their relationship deepens and they discover one another's obsessions - Kanazuki's being black magic while Honey's is cake and small things. In an omake, they marry, making Honey the first Host to do so.