Otori Kohaku was an existing 3D model and animation character, Unity-chan, before her VOCALOID announcement, with her original debut in December 2013. She was created as a mascot for Unity, a cross-platform game engine developed by Unity Technologies,- for the Japanese division. She grew quite popular with gamers and interactive application writers, as assets for her character were available as a free download. This led to her appearing in a variety of developers’ projects.
As she was recorded for Vocaloid4 and not Vocaloid3, one of the developers known as “Baba” reported in an interview that the vocal had a different sense of direction. The change of Vocaloid 4 vocals resulted in the focus laying on the vocalists vocal characters and traits, although the methods used for Vocaloid 3 were reported to be easy to fit for music. This meant learning about the character of “Unity-Chan” and how to bring out best the vocalists traits for this.
On August 26th, 2015, she was officially announced for the VOCALOID platform as “Unity with VOCALOID”. She was expected to release around December and would be compatible with VOCALOID for Unity and the VOCALOID4 engine.
Note:This is japanese and english language libraries