I don't know if anyone knows this band but they sang one of the songs in Durarara ! If i'm not wrong its the Second opening song! I heard it and got ADDICTED to the song!! And they also sang one of the songs in Ao no Exorcist. The song with vulgarities in it (LOL), i think its the second opening song! They have really catchy songs!
This is the youtube link for Complication
which is the Durarara song! Its awesome!!