[Emperor Charlemagne]

If it's heroes versus villains you want, here are some well-known and not so well known cool tunes:

Maria's Theme for Maria the Valkyrie vs. Melissa's Theme for Melissa the Dark Angel in Knights in the Nightmare (though some might say the real villain is Zolgonark...)

Simon Belmont vs. Dracula
-Castlevania, of course

Phoenix Wright vs. Godot or Dahlia
-Edgeworth is not a bad dude, he's a rival. These two are the true bad dudes (but in Godot's case, he's a bad enough dude to rescue the president)
from the Ace Attorney Series

Unlock the Real Me for Terry, and, uh, well, 'VS Mint 1' for the bad... girl of the game, Mint. You know, from Contact, for the DS! Right? Eh?

Yeah, no one played this game, and not one would remix music from it.
Though, if this ever does get off the ground, and I get good at remixing, I'd like to try my hand at remixing a song or two from this awesome and overlooked OST.

lolol cloud vs sephiroth