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At the time of his original sale, Vocaloid was not yet a well known product, and synthesizing software was only considered successful if it sold more than 1,000 units. However, Kaito managed to sell only 500 units—deeming him "a commercial failure." In contrast, his counterpart, Meiko, had sold 3,000 units in her first year.

Kaito's initial failure was one of the main reasons why other male vocaloids have not been developed for a long time after his release. The male voicebanks had so little demand at that time. However, later interest in Kaito arose and Kaito sold well enough to later claim the second best seller of the year in Nico Nico Market in 2008. From 2009 up until late 2011, he was in the top 10 best selling software of Crypton Future Media often competing not only with Vocaloid 2 era voicebanks, but on occasion outselling them.

Kaito's Update and Append in 2011

The first commercial usage of the Kaito Append was from the album "VOCALOID民族調曲集", which features Kaito Append singing the song "千年の独奏歌 (kaoling mix) / yanagi". The VOCALO APPEND album later used beta voicebanks of Kaito's "Normal", "Soft", and "Whisper" voicebanks singing "Lost Destination" with Kagamine Len Append.

In January, CFM noted that the silhouette has a transparent muffler. On February 17th, 2011, Crypton released a temporary silhouette of Kaito's Append. They said that it has not been decided whether he will have a transparent muffler or not since there was previous outcry from fans.

In March, Wat mentioned work on Kaito's vocal had encountered a problem which halted the work. He also did not know the release date yet.

In April, work on Kaito's voice resumed. Work on the vocal along with other protects had come to a hault.Wat mentioned wanting to do a vocal with a soft tone to it as well as a down toned voice.The voice of Kaito was going through checks on α stage. On the 13th April, 2011, it was confirmed 6 vocal expressions had been recorded, two of which were dropped and the remaining were being brought forward with one having reached a completed alpha stage already. The Character Vocal (Hatsune Miku, Kagamine Rin/Len and Megurine Luka) series Appends had been created from vocal performance of their voice providers. The new Kaito Appends were created by adding echo, force and tension to the samples.

Crypton Future media also noted that several voicebanks had been recorded with new high tech microphones through a series of trial and error instead of the standard U87ai, these were;

•Vivid

•Solid

•Power

These vocals were done as a series of experiments with new equipment using Naoto Fūga's voice. Kaito's voicebank for "Whisper" and "Soft" were released soon after the first 3 append voicebanks he received. 

Kaito's Update in 2012

In Feb Wat discussed the differences between the CV series (Hatsune Miku, Kagamine Rin/Len and Megurine Luka) and Kaito/Meiko and stated their updates were being adjusts using editing techniques to achieve the results, whereas the CV series Appends had been done by acting performance. English Kaito voicebank was reported to have received adjustments to a few of it diaphonetic data in Feb 2012.

Crypton Future Media began looking for Japanese producers who can use English capable Vocaloids to work with for the English version. Kaito himself is currently being compared to overseas male English Vocaloids. On 23rd of Feb it was announced that they were able to talk about the progress of both Japanese and Kaito voicebanks in production. The company is exchanging VSQ files with producers to see how the current English Vocaloids compare with Kaito.Several overseas producers were now taking part with Kaito's production. Kaito's double vowel and vowel to vowel sounds had been adjusted after a report came back on him.

It is confirmed that Kaito's clothes would not change in March 2012, they will just get a facelift. The boxart will also use a 2.5D style drawing. In early March 2012, Kenmochi Hideki was given the voicebank to make further adjustments to. English vocal was sent to Kenmochi Hideki to check the vocals. Crypton noted that all that was left over was that Kaito's vowels had to be adjusted.

In April, Crypton commented on "Whisper" use of triphones as "wonderful". Kaito's "Normal" voicebank was also officially declared as part of the new version. Wat also confirmed the manual will contain a history of Vocaloid Kaito.

Checks were run on Kaito's voice in October. Further adjustments were made to Kaito and Miku in early October prior to their vocals demostration. Crypton were also considering what to call the default vocal for Kaito and had suggested names like "Neutral", "Natural" and "Default".

A English demo of Miku and Kaito was shown NYCCon 2012, both are still in Beta version. Kaito's V3 "whisper" and V3 vocal were shown. Kaito's release of his English vocal was expected "by the end of this year or the begining of the next".

In December it was reported that news on the update of Kaito is due within the next few days.

According to Crypton Future Media, there had been some delay on Kaito's V3 version due to their desiring to include "Piapro Studio" with his package.