Two alignments are opposed to impose their magic, the Dark one and the Light one .

Once upon a time, dear reader, there was a god, his name was Gothar. Not a particularly nice fella, but hey, when you have had eternity to contemplate your naval only to discover it is a naval, you might be a bit pissed too. So he had children. The world he made for them to play in was split in to kingdoms. But some of his kids were errant little shits. Quite the destructor of the toys he had made. One of them, Neutra, got pregnant. No one is really sure how that happened, but the uncles and aunts were all a bit jealous of the kid, who was named Dragoon. They all saw great power in him and they coveted the child, and plotted and schemed as only bored immortals can do. So Grandpa Gothar locked his grandson in to the moon, as all good grandparents do when their own parenting skills were insufficient to pass on any sense of decency through the generations. There the young god grew foul. He festered and stewed in his prison. He took on the form of his dark thoughts. Unbeknown to his family, the moon rock actually held magical power. Over the millennia, the rocks drew their power from their surroundings. One side from the sun, and the darkness of the void of the galaxy on the other. And in between, the son, Dragoon, was ever more capable in the ways of the magic. Soon he escaped. And the moon shattered, spreading its infused rocks across the world below. Some dark. Some light. In time, the people of the land discovered the crystals and began to experiment. They discovered also that ancient towers could be powered by the crystals to give protection and extra magic regen capacity1) . As the years went on, those drawn to the dark crystals recognised that the power was there, and should be harnessed to fullest extent. Those who had been using the light crystals recognised that they should be brought in to balance with the land.*

1) http://web.archive.org/web/20030206081111/http://darkandlight.com/modules.php?op=modload&name=FAQ&file=index&myfaq=yes&id_cat=3&categories=General&parent_id=0