Story is about 3 descendants of humans: the Corite, an elfen type race that specializes in magic, the Bellato, dwarven people who excel in mechanics and can drive mechs, and the Accretians who are basically robots.

They are all fighting for resources. The Corites fight because they believe those resources are holy (ie Holy War), Bellato fight out of pure greed and the Accretian fight for the survival of their race.

That pretty much sums up the basics.

Edit: http://www.codemasters.com/rfonline/news.php