The essential gist of the game is this: Think of any long-gone deity from mythology. Imagine they once truly existed. Now imagine that they aren't truly gone but instead their essence lives on, is reincarnated inside of that guy who sits next to you on the bus every day. Or Maureen from Accounting. Or maybe even you. They could be anyone, young or old, male or female, any race, anyone.
The old deities once existed, once walked the Earth, and mortals trembled at their names. Long ago, they each slowly faded out, their existence only remembered as fables and tales. During this decline, one deity gathered up and called upon his or her last reserves of power and influence to create a reprieve, of sorts, for them all. They would find their essence, their souls if you will, not dissipated amongst the matter of the Universe but instead reborn inside a mortal body. They would be mortal, yes, their power would be greatly diminished, yes, and they might not even remember what they once were, but they would at least exist.
To give you some further details about the game: Deities of any mythological pantheon may be represented. It is more than possible, however, that just because they were Greek or Sumerian or Norse or Polynesian or African doesn't mean that they have to be reincarnated into a mortal of that descent. Just because they were once male doesn't mean they have to be reincarnated male and vice versa. Some of them remember from birth what they once were. Some never find out. Some come to this realization later in life, some earlier, it's really up to you, the player. Some may only ever have their memories and others may develop powers concurrent with the type they would have had as a deity. A note of caution though, reincarnated deities are not immortal. They can die. They can fall ill. They can bleed. Both true mortals and incarnations of past deities are welcome as characters. Finally, Chaos Theory takes place in modern-day Washington, DC and its surrounding suburbs.