Lucidity takes place in the world of dreams -- a world filled with Dreamers, real people who dream without awareness, and Lucids, those few who understand where they are, have a sense of self, and can learn to manipulate the dreamworld to their own advantage. The players, naturally, are Lucids.
Yet "a sense of self" only takes you so far; the Lucids have snatches of remembrance from their former life, and the process of character creation is, in fact, a matter of deciding how many memories you sacrifice for the sake of power and sanity -- and what things you do remember. You can bargain with the Dream King (that is, gamemaster) for some additional memories, by taking disadvantages in exchange.
