Kisaragi Koi is the male representative for the month of February. He is an idol under Tsukino Talent Production, and is a member of the unit Six Gravity. His producer is Nijihara Peperon, and he is voiced by Masuda Toshiki.


Koi is a fair-skinned young male, with short bubblegum-pink hair and slightly darker pink eyes. The hairpins he regularly wears are gifts from his younger twin sister Ai. While initially one of the shortest among the male idols, he has experienced the most height growth in the past few years. He is also the youngest among the members of Six Gravity and Procellarum, having to debut at the age of 17.[1]

His theme color is pink.[2]


Koi is a naturally friendly, amiable type of person. He is good at socializing, making him a person with lots of friends from either gender and always encourages those who feel down. He is also described to be earnest, hard-working, straightforward, and quite well-informed. Because of this, he's made some startling connections.[1] As a result of his naturally extroverted personality, Koi gets along very well with their staff members.

Furthermore, he resembles a big brother's role by looking out for everyone, despite being doted upon by those older than him. He's also quite the mood-maker, and plays the funny man role and can throw sharp retorts, making him a reliable member of his unit.[1]

According to his profile, while he may look like a player, he has a strong moral sense.[1]


Koi is one of the twin children of his unnamed father and unnamed mother, a former Goddess. His younger twin sister, Ai, is also a Goddess Candidate. However, both Koi and his father are not aware of the Moon Society and Mrs. Kisaragi and Ai's standing as a former goddess and goddess candidate, respectively.


Initial (2012-2013)Edit

Age: 15 years old
Height: 170 cm

Like his classmate Kakeru, he made his debut during his first year in high school, although it was not specified how Tsukino Mikoto had scouted him in the first place.[3]

After being scouted, he, together with Shiwasu Kakeru, Mutsuki Hajime, Yayoi Haru, Uduki Arata, Satsuki Aoi, move into the Tsukino Dorms and the six subsequently form the idol unit Six Gravity.[4]

Not long after, upon finding out that Six Gravity's sibling-slash-rival unit Procellarum has been officially announced, Koi is very much shocked by the idea of having another unit under the same company they have to and the two units proceed with their idol work individually and side-by-side.[5]

Also, Six Gravity's Tsukiradi. broadcast, which he and Kakeru hosts together, celebrates its 20th broadcast sometime within the year.[5]

In December, he and Kakeru are also the first to release their duet CD.[6]


Age: 16 years old
Height: 173 cm

Kakeru finds he finds an abandoned shiba breed puppy during their photoshoots and is compelled to keep it, already giving the name "Croquette". The pair then managed to convince Hajime and Haru allow the pair to keep the puppy.[7]

Also, Six Gravity's Tsukiradi. broadcast, which he and Kakeru host together, celebrates its 50th broadcast sometime during the latter part of the year.[8]

Koi, together with Procellarum's Minaduki Rui, Fluna's Hijiri Kurisu, and Seleas' Tendouin Tsubaki host Tsukiuta.'s first live event, "Tsukiuta. Haru no Fan Matsuri 2014".


Age: 17 years old
Height: 175 cm

He and Kakeru are currently in their third year, both deciding to pursue their university studies and preparing for their university entrance exams.

In February, after all the duet CDs for both Six Gravity and Procellarum are released, Six Gravity releases their first CD as a unit, entitled "GRAVITY!".[9]

Six Gravity and Procellarum also hold their first live together, with all their songs featured in their second set of solo CDs, together with their cross-talks in-between solo performances during their collaboration live. He and Procellarum's Kannaduki Iku released their CDs in October.[10]

Present (2016)Edit

Age: 18 years old
Height: 176 cm

Six Gravity, together with Procellarum, and goddess candidate units and Seleas, celebrate the release of their individual best albums.[11]

He will be starting his university studies this coming spring with Kakeru, who will be going to the same university as him, and Iku, who will be attending a different university.[12]


Kisaragi AiEdit

Koi cares deeply for his younger twin sister and dotes on her quite often. While Koi may be the older twin and plays the big brother role well, people say that Ai is more reliable.[1]

Shiwasu KakeruEdit

Koi and Kakeru became instant friends when they first met at their missionary private high school.[4] He and Kakeru are often paired up together when it comes to idol work. His relationship with Kakeru is close enough to the point that they have fights.[13]

Since Koi has a generally lucky constitution, he with his good luck and Kakeru with his bad luck even each other out.[13]

He and Koi have also established a rule of sorts that if one of them can or has the time to do so, he has to take Croquette on a walk.[7][13]

Mutsuki HajimeEdit

Koi initially referred to Hajime as a powerful-looking person, similar to the last video game boss. Koi looks up to Hajime a lot, similar to a puppy looking up to its master, and holds a lot of respect towards him. The first time they had all gathered as a unit in the dormitory, Koi was the first to be subjected to Hajime's "Iron Claw", and among the younger idols is the one who is subjected to it the most.

While Koi's bright, lively, and rather a spontaneous personality is quite the opposite of Hajime's personality, Hajime harbors a soft spot for those younger than him and treats Koi (and Kakeru) as if they were his younger brothers.

Hajime also tutors Koi quite often, mainly due to Koi's naturally bad English skills. While it seems Hajime's tutoring method can be rigorous, Koi's grades have improved considerably, to the point that Koi's mother thought that Koi had been attending cram school.

Yayoi HaruEdit

Koi likes and respects Haru, and two get along quite well. Haru sees the Koi and the younger ones as those who liven up the dormitory and treats them as an older brother as well as serves as some sort of mother-figure. Also, Haru sees Kakeru and Koi as most suited to being the hosts of the Tsukiuta. Radio and places a lot of trust upon them, although sometimes questions the jobs given to them as that different from what idols usually do.

Uduki ArataEdit

Koi instantly develops a certain level of dislike towards Arata, and vice-versa, and two lapse into an often-bickering relationship, often over trivial things, not due to opposite views, but because they're on the same wavelength. Instead of mutually understanding each other, they often clash instead. However, despite this, the two actually do get along well and agree on certain topics, as noted by their fellow unit members, but they vehemently deny this.

Satsuki AoiEdit

Aoi sees Koi as a cute younger brother. Koi, on the other hand, recognizes Aoi's status as a good-looking person. According to Kakeru, Koi usually develops a particular dislike for naturally good-looking people,[4] but Koi can't develop any negative feelings towards Aoi and is grows attached him, hoping that some of his high-specs would rub off on him. Nevertheless, he treats Aoi no differently than everyone else, seeing him as an older brother as well as a reliable coworker.

Haduki YouEdit

Koi gets along very well with You and tends to get excited over their random conversations.[14]


Solo CDsEdit

Nijihara Peperon × 
Kisaragi Koi
Radical Lovecal
Nijihara Peperon × 
Kisaragi Koi
Tsukiuta. THE ANIMATION Vol. 1
Nijihara Peperon × 
Kisaragi Koi
Tomorrow's Color
Nijihara Peperon × 
Kisaragi Koi

Duet CDsEdit

Datte Mada Mada Avant-Title
Satsuki ga Tenkomori × 
Shiwasu Kakeru &
Kisaragi Koi
Nijihara Peperon × 
Kisaragi Koi &
Shiwasu Kakeru
Chocolat no Mahou
Nijihara Peperon × 
Kisaragi Koi &
Kisaragi Ai

Unit CDsEdit

Tsukino Mikoto × 
Six Gravity
Various × 
Six Gravity
Tsukiuta. THE ANIMATION Theme Song CD
Tsukino Mikoto × 
Six Gravity & Procellarum
Tsukiuta. THE ANIMATION Vol. 7
Tsukino Mikoto × 
Six Gravity & Procellarum

Drama CDsEdit

Tsukiuta. Drama!
Six Gravity
Tsukiuta. Art Book
Six Gravity & Procellarum
Ikebukuro Tsukineko Monogatari
Six Gravity & Procellarum


  • His name reflects many of his traits:
    • Kisaragi (如月) is the archaic name for the second month of the lunar calendar; poetically, February.
    • His given name, Koi, comes from the character 恋, which means "love".[15]
      • His sister Ai also shares her namesake with another Japanese character for love: 愛. The difference between koi and ai is as follows: koi more often refers to love in a physical form and is the "romantic" or "passionate" type of love; ai on the other hand, refers to a more general feeling of love.[16]
        • Interestingly, in the term renai (恋愛), which translates to "romantic love", the character for koi comes before ai, similar to how Koi was born before his younger twin Ai.
      • February is also widely popular for Valentine's Day, a day wherein people exchange tokens of affection.
  • Similarly, his official fanclub also reflects his position as a February representative:
    • His and Ai's official fanclub name, amor, is the Latin word for "love". This is in keeping up with the February pair's general motif relating to love.
      • Their fanclub motif is that of a heart, also reflecting their general motif relating to love.
    • Their crest is that of the Japanese plum (梅, ume), which is also a popular flowering plant during Springtime, quite similar to the cherry blossom.


  • His strengths and favorites include his family (his younger sister in particular), sweet things, chatting, being fashionable, games in general, karaoke, comedy, anime, manga, and things related to designing.[17] He also has a hobby of checking the new items at the sweets corner at convenience source.[18]
  • He is right-handed.[19]
  • His eyesight (both eyes) is 1.5. To keep his eyesight from going bad, he makes sure to rest his eyes and eat blueberries.[20]
  • He resembles his father and was voted the most dog-like.[21][22]
  • He currently owns 15 hairpins received from Ai.[2]
  • Fond of sweets, and was very glad to receive an all-you-can-eat cake buffet ticket from a woman who did their make-up once.[23]
  • He likes his eggs sunny-side up with soy sauce, his fried egg rolls sweet.[24]
  • Chisa was the one who gave him the nickname Koikku. The reason behind the naming was that she heard from Ai that he once groaned about TOEIC (spelled トイック, TOIKKU in Japanese) test score at home.[25]
  • Yaegashi Kensuke, from the ALIVE Series' unit Growth, is also known to refer to Koi as Koikku. According to him, Koi and Arata are quite skilled at wotagei, which is the type of cheering and dancing gesture done by fans of Japanese idol singers.[26]
  • He considers English his natural enemy.[27]
    • Despite this, he can pronounce English lyrics quite well by grasping the lyrics' nuance. He has admitted that he doesn't understand much of what he's singing in the first place.[27]
  • He states that he has neither received the true feelings kind of chocolates for Valentine's nor has been confessed to.


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