This battle theme is a remix of FFVI - Decisive Battle.
Not only that, it's the theme you will hear much in every non-boss battle in my game, Bobo RPG. For every boss battle there are other themes you will hear, but here is my personal best.
Download link: http://www.mediafire.com/download/k05i6nkbkjvp7xf/Bobo+RPG+-+Battle.ogg