Both songs came from fripSide‘s 2010 single, 「future gazer」 which is an OP single for OVA of To Aru Kagaku no Railgun, which is To Aru Majutsu no Index side-story. Lots of their songs were featured in Konami’s Dance Dance Revolution rhythm game.
「fortissimo-the ultimate crisis-」
Lyrics: yuki-ka (full lyrics)
Composition/Arrangement: Satoshi Yaginuma