In Nobilis, players take on the roles of the Sovereign Powers, each the personification of one single aspect of reality: Night, or Roads, or Ecstasy, or Chains. Once human, each character has been forever twisted and changed by the addition of a single soul-fragment from their Lord or Lady Imperator: giving them awesome power and terrible responsibility.

Heaven and Hell, Yggdrasil the World-Ash, the Angels and Devils, the Giants and the Old Gods, all are real; each each with aeon-old plots and rivalries. All are united in the Great War against the Excrucians, whose goal is to destroy all Creation, but divided by their own rivalries and feuds.