In the Dungeons & Dragons fantasy role-playing game, Baator, also known as the Nine Hells of Baator or the Nine Hells, is a lawful evil-aligned plane of existence. It is one of a number of alignment-based Outer Planes that form part of the standard Dungeons & Dragons (D&D) cosmology, used in the Planescape, Greyhawk and some editions of the Forgotten Realms campaign settings.. It also exists as one of a number of faith-based Outer Planes that form part of the separate 3rd-Edition Forgotten Realms cosmology, used in the setting of the same name.