Toshihiko Karasawa

He is a producer at the major music company Key Time, and is also responsible for the popular band AZALEA. He approached AZALEA and repproached them as a washed up unpopular band, and offered them an opportunity that will turn them into a popular band within two years, but under the condition that they'll sing his songs.

[Spoiler] He will eventually transform Azalea into a commercial success by changing their appearances and style. [/Spoiler]

(Source: Ya Boy Kongming Fandom Wiki)