Magic is a staple in many RPGs. The ability to in some way interface with the unseen, or utilize some latent mystical power to the effect of greatly changing the world around you is incredibly cathartic and has seen some excellent interpretations in games from a variety of sub-genres and themes. Maybe magic means dark necromantic power for one character, or holy healing magic to another. One of the oldest forms of 'magic' in the real world, however, has always been astrology.