fripSide is a Japanese pop and trance duo originally formed by composer Satoshi Yaginuma (Sat) and singer Nao in February 2002.

In a 2008 interview, Satoshi said that he was a fan of TM Network and its member Tetsuya Komuro in his elementary and junior high school days and began to produce his music at the age of 14.

[1] When the group started, they were releasing their songs on the Japanese amateur and indie community, Muzie.

fripSide's albums were always high in sales at Muzie's online CD shop.

[4] Voice actress Yoshino Nanjō replaced Nao as the new lead singer of fripSide.

Eternal Reality (2nd opening theme for Toaru Kagaku no Railgun S)2A.