Here's my idea for the story of the single player campaign:
We have come to learn that the Vasari are being chased by twisted, powerful, mutant Vampiric Vasari with psychic powers! In the meantime, the Vasari and the Advent squash and eliminate the pathetic and socially intolerant TEC, the very race that previously expelled the Advent for being sexual deviants and pagans. After some initial skirmishes the Advent and Vasari realize that they are on the same wavelength and come to respect one another for join forces to fight against the evil Vampiric Vasari.
