The lead singer on Supercell’s eponymous first album is Hatsune Miku-a Vocaloid character created by Crypton Future Media with voice synthesizers. A virtual superstar, over 100,000 songs, uploaded mostly by fans, are attributed to her. Supercell is a Japanese creator music group with the composer Ryo leading ten artists, who design album illustrations and make music videos. These videos are uploaded onto Niconico and other video-sharing sites. By the time Supercell was released in March 2009, the group’s Vocaloid works were already well-known to Niconico users and fans. This book explores the Vocaloid and DTM (desktop music) phenomena through the lenses of media and fan studies, looking closely at online social media platforms, the new technology for composing, avid fans of the Vocaloid character, and these fans’ performative practices. It provides a sense of how interactive new media and an empowered fan base combine to engage in the creation processes and enhance the circulation of DTM works.