Hatsune Miku
Hatsune Miku was the first Vocaloid developed by Crypton Future Media after they handled the release of the Yamaha vocal Meiko and Kaito. The name of "Hatsune Miku" was conceived soon after the Vocaloid 2 announcements, when an English and Japanese vocal were developed for the character. The intended design was delayed and later used for Megurine Luka instead. Miku was intended to be the first of a series of Vocaloids called the ""Character Vocal Series"", which included Kagamine Rin/Len and Megurine Luka. Each had a particular concept and vocal direction.
Utau
Later, the UTAU software would have its own impact on Vocaloid and other vocal synthesizers, with a number of vocals either referencing UTAU or being produced for the engine to begin with. For example, Megurine Luka V4x was influenced by the UTAU vocal "Gahata Meiji". Wat from Crypton Future Media also spoke to someone very familiar with UTAU and said that the conversation was "very interesting". Macne Nana of the Macne series later would become both a UTAU voice and a Vocaloid voice. The voice provider of English Vocaloid Ruby, Misha, had previously produced a Japanese-language UTAU named Makune Hachi (MAKU音ハチ). In addition the vocalist for Dex, Kenji-B, created for UTAU and AkiGlancy, the vocalist behind Dex's partner Daina, gave her voice to a UTAU called . After the release of Vocaloid 3 vocal Tohoku Zunko, her two sisters Tohoku Itako and Tohoku Kiritan received UTAU vocals, Kiritan would later go on to have a campaign for her to become a Voiceroid.