This is a really amazing song originally composed by Bosukete P (Bosukete-P) Originally sung by KAITO & MEIKO http://www.nicovideo.jp/watch/nm4342917 Teto cover by naruko http://www.nicovideo.jp/watch/sm14023676.
The vocal on this song was made using the software UTAU, which is a Japanese singing synthesizer, similar to the Vocoloid one by Yamaha, but UTAU is freeware. The voicebank used here is Kasane Teto, one of the more popular UTAO voices. I’ve become obsessed with this technology as of late and am desperately trying to learn how to use it so I can post a good tutorial of it in the future. In the meantime, you can enjoy this amazing song and entertaining video!