If you're talking about the music that plays during combat, it's a track called "BGM Scene6 Valkirie FSPC", from the Future Steam Punk resource pack.
I like the pack in that pretty much every song in the pack is really catchy, and I enjoy listening to them. But I've found that it's kinda hard to actually use a lot of them in RPGs, because almost every song has such a fast tempo that they just don't really seem to fit many situations. I'm thinking that whoever composed the music probably didn't actually do so with the initial intention of it being used in RPGs. But it turns out that the pack fits a game like this one pretty well.