As has already been suggested, the multiverse concept is that the infinite Creator could not adequately express Himself in a universe, so he created a multiverse, a very large but finite number of universes more or less similar to each other. This creation was accomplished by an original creative act followed by multitudinous acts of divergence: at each choice, at each turning in the path the universe took, it split into two parallel universes. Thus, all diverge at some point from a common history, but in many, earth was never created, and in others its history is very different.
It is an illusion of this divergence that more worlds are similar to ours than are different from it. Perhaps this is partly explained by the small differences rule; a world in which a recent war was not fought, or a major figure not assassinated, or a discovery not made strikes one immediately as different. Another world in which dinosaurs still roam the earth would be more different; but would we notice if pteranodon never appeared? That could be a major difference between two such worlds (more drastic than who first walked on the moon), but to us the distinction is small compared to whether or not man appears.
Still it must be noticed that characters seem to visit more worlds with humans than not, and while a theological explanation of this has been offered (since Reason Himself took this form once, how could reason take any different form thereafter?), it seems more likely that there is an explanation in a tendency for versers to stay closer to "home", that is, to appear more often in worlds nearer in divergence to one's own. Thus we find that there are close and distant parallels, diverging more recently or more distantly from a common path.
In this game, all real and altered moments in history are possible. Myths from the ancients or the moderns (Paul Bunyan as surely as Apollo) can relive their stories. The stories of books, movies, television shows, poems, all can be reenacted and reformed by verser characters. Other game worlds can be entered, explored, pillaged, and exited again. Every world that ever was or is or will be or might have been exists somewhere in the multiverse; and any time a character dies and again opens his eyes, he is in another one.
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