The warriors of Darkness actually combated the light. As Light and Dark are simply powers that balance each other out, neither being evil, the fact of the matter is, it's how they are used that dictates what kind of warrior comes about. The warriors of light combat the darkness, the warriors of darkness combat the light. This would fit in with the fact we have seen another crystal, similar to the one of light, but in darkness. So it IS highly possible, with the addition of the crystal tower that part of FF3's storyline will seep into our world here and I would not mind at all.