The product's name was invited to be chosen by the public, and "KAITO" was selected from among the applicants, which was Shu-tP's offered idea. One of the reasons why his name "KAITO" was selected was because it would be easy for non-Japanese speakers to pronounce, and it looked fitting with the name "MEIKO" when they were put next to one another.
KAITO's codename of "TARO" likely came from "Yamada Tarō (山田太郎)", a placeholder name for male characters and the Japanese equivalent to "John Smith".
The illustration was done by Takashi Kawasaki. Crypton did not set his character and profile except for his package design. Like MEIKO, he was not made with the aim of giving character or personality to vocal synthesis software. This was also emphasized during the development of the V3 vocal banks, with Wat stating how different the intention of the CV series was to the intention of KAITO and MEIKO. This led to the updates taking a totally different course of development in comparison to the Appends of Miku, Len, Rin and Luka.
KAITO's muffler has become one of his most iconic items. During his V3 update, there was fan outcry over the idea of it being made transparent. In answer to this, Crypton stated that cloth can be made out of anything, including plastic; there was a lot more freedom with it than many realized.
KAITO has no official given age. However, in Maker Hikōshiki Hatsune Mix he is usually portrayed as a middle aged man by KEI. Despite this, what the artist depicts in the comic is not official, as he mentioned in a magazine interview.
Because of the story of his rediscovery in 2008, KAITO was often depicted with ice cream. This gave birth to the "Item War" Internet Meme tradition.
The act of putting a character on the boxart was carried over to following VOCALOIDs to encourage creative activities by individuals, expanding the characters based on each user's individual needs.
KAITO's V3 release repeats many aspects of what made the CV series popular, and he is already due a series of "beginners guides" in magazines such as DTM.
KAITO has had a few figurines based on him. Despite being older than the CV series VOCALOIDs, KAITO's merchandise tends to sell particularly well. The Nendoroid KAITO figurine had high demand, causing the original to have a second re-issue. A second version of the Nendoroid KAITO has been released, apart of the Cheerful Japan line and a Figma figurine.
KAITO's rise to fame was by lucky circumstances, since KAITO was "a commercial failure" when he was first released and few had any interest in him previously. Upon release, he sold only 500 units in his first year, in which he needed to sell 1,000+ units to be counted as "successful" commercially. After his success, 100 units were sold in Jan 2008; this amount began to rise rapidly. By June 18, 2008, KAITO was reported to have now sold an additional 1,000 units, this was twice as much as his initial sales. This also shocked the Vocaloid developers at Crypton Future Media, who were surprised by the sudden attraction to old VOCALOID software "KAITO".
At the height of his sales, he was the only one of the two VOCALOID engine vocals to have a consistent ranking as one of the Crypton's Top Ten Products. In 2010, KAITO was ranked as the 7th most popular VOCALOID product they sold. In some instances after his rediscovery, VOCALOID KAITO was even more popular than the VOCALOID2 engine Appends for Miku and the Kagamines. His design has also spawned many producer based derivatives.
Unlike KAITO, KAITO V3 was very well received upon release. Crypton updated their music software sales page with those of March 2013 in the following month and the presenting data that showed KAITO V3 was an all-time topper in sales. He managed to even surpass MEIKO V3 in sales and in August 2014, was in 3rd place while she remained in 6th; 1st and 2nd were held by Hatsune Miku V3 and Hatsune Miku V3 complete.
Crypton Future Media's top ten products list showing KAITO in 10th place (12/10/2011)
KAITO V3 software outsold Hatsune Miku; ending up in the 1st place for sales of March 2013
KAITO V3 holding the 3rd place spot for August 2014
The story of the sudden change in opinion of him occurred on September 16th, 2007, when 'Tatsunami' uploaded a parody of the song in Higurashi no naku koro ni, "A Request From Hatsune" onto NicoNicoDouga. During this time, Miku was extremely popular on NicoNicoDouga, yet almost nobody knew of KAITO, let alone produced songs using him. The video begins with the words "please sometimes recall [KAITO]," as well as Miku saying "where are you and what are you doing now?" which is from the song "Dear You".
About four hours later, "An Answer To Hatsune Miku" was posted by 'Ice-P'. In this video, KAITO responds with, "yes? I was eating an ice cream," and then proceeds to sing a cover of "The Ice Cream Song" (originally sung by Saeko Shuu in 1960). KAITO's last dialogue in this video is "Miku, let's eat it together next time." It just so happened that Ice-P was producing the cover when he saw the video Tatsunami uploaded. This introduced many people to KAITO and gave him his signature item.
After the turn around in popularity, many producers began to revalue KAITO as a VOCALOID, which became much of the reason why KAITO stayed popular. His voice became acknowledged for its all-round usefulness and in turn for being highly compatible with the VOCALOID, giving him flexibility in his performance. KAITO proved useful for variety of male roles that other Japanese male VOCALOIDs often did not suit; even though he was the only Japanese male powered by VOCALOID and the engine was well known for being difficult to work with in comparison to VOCALOID2 and later. Even Wat himself reasoned that much of his popularity was owed to the capabilities of his vocal. Wat quoted one of his acquaintances upon their reaction to KAITO's voice. He stated they were shocked at hearing such a "beautiful male voice".
Kaito's failure initially led to the focus on mostly female vocals in Vocaloid projects by Crypton Future Media. The legacy of this consequence is that the majority of the vocals produced for the Japanese version of Vocaloid are female rather then male.
An independent search on Nico Nico Douga revealed that most VOCALOIDs had less than 1,000 videos uploaded on Nico Nico Douga in 2011 between July 1st and December 15th. However, KAITO managed to make it into the top six of a few lists. KAITO was the 6th most popular VOCALOID in terms of uploads, receiving 1404 uploads. KAITO had the 6th highest number of views with 1,561,894 views and 118,479 mylists. KAITO did not make the top 6 average list, however, he was the 3rd most popular VOCALOID based on the mean number of views with 414 views and 19 mylists, which is a more truer reflection of his popularity.
Since Yamaha and Crypton printed different dates for KAITO's release (Yamaha: 14th, Crypton: 17th), some fans within the Japanese VOCALOID community celebrate KAITO's release date anniversary during all days between the different dates.
When it came to the KAITO update, the voicebanks went under much experimentation throughout the developing process. This was because although Crypton were veterans at producing VOCALOID voicebanks, they did not have so much experience with masculine toned vocals such as Fuuga Naoto's. This was due to the fact all of their other VOCALOIDs intended for the consumer market had come from female vocalists.
Owed to the difference between VOCALOID KAITO and VOCALOID3 KAITO, Wat himself referred to the two packages as like "brothers" due to their very separate natures.