fripSide is celebrating its tenth anniversary with a CD/DVD/BD called Decade, featuring both its original vocalist Nao and its newer vocalist, Nanjou Yoshino. Release date December 5th. The short version of the PV has been released. Yoshino is the one wearing a belt:
fripSide began in 2002 as keyboardist/composer Sat and vocalist Nao. Nao left for a solo career in 2009 and seiyuu Nanjou Yoshino took her place.
fripSide Nao began doing game themes in 2007, with the OP for Koihime Musou, "Flower of Braery." fripSide Yoshino's first release was "Only My Railgun," the theme for To Aru Kagaku no Railgun. This became the group's best seller ever. fripSide went on to do a second Railgun theme ("Level 5: Judgelight"), the theme for a Hayate series ("Heaven is a Place on Earth"), and a theme for a Railgun game ("Way to Answer").
The dancing man who makes a brief appearance is eccentric comic Ruu Oshiba, who I think hosts the live show that is on the DVD/BD.
There are plenty of fripSide videos on YouTube.