There are 3 artists named ZZ:
1) ZZ (zi, zi) is a Japanese rock band. Their first album (NO WAY OUT) was released in 2003.
One of their songs, "Dang Dang", was used as an opening song for the anime "Eyeshield 21". Another, "A to Z", was used as an ending song for the anime "One Piece". Their song "Samurai Blue" was used as Japan's official theme song for the 2006 World Cup.
Sotaro (vocals, born May 27 1976)
Erichi (keyboards, born April 9 1976)
Matsuura (drums, born June 1 1964)
Kohsuke (guitarist, born June 24 1976)
Kyama (bassist, born September 7 1979)
2) zz is a doujin arranger of the circle 巣鴨北口店, which includes ノーザン・キラー
3) ZZ is one of many one-time-used aliases of NAOKI used in song "The legend of MAX" from Dance Dance Revolution game (8th mix -Extreme-).