There are more than one artists with the name Co3:

1) (Typset as 'co3') A side project of the band FACT. Bares the same name as one of FACT's songs. They like to feature obscure rappers such as 'Adskillz', who later, in 2012., joined the FACT
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Releases:

2011.03.16 (EP) co3

2) David Wellendorf, is currently living in Denmark, where he plays some gigs with his band and make some music on his own, under the name Co3.

Co3 has a lot of Musical Experience, as he have been involved with a lot of different bands, and have listened to music, very heavily, since he was 6 years old.

He started to make his own at the age of 10, involving a guitar and Ejay. Lots has happening since then, and now Co3 feels ready to publish his music.

3). An italian soundsystem from Milan.
http://www.myspace.com/co3sound Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.