"Nobilis" draws on many sources, including Christian and Norse mythologies, but adds numerous unique details to its setting. Though the everyday world in the game appears much like our own, it is actually only the Prosaic Earth, a lie that the world told to itself in a desperate attempt to explain suffering, and a rationalized delusion which conceals the true reality that would plunge most mortals into madness: the Mythic Earth, an animistic world where everything has its own sentient spirit. In the Mythic, the earth is really flat, and hangs somewhere among the vast boughs of the "world-tree", Yggdrasil. Countless worlds dot the branches of this world-tree, but at the top is Heaven, which is inaccessible to all but the angels (only one human soul in a billion is not turned away) and is the source of all beauty. Beneath the earth, in the roots of Yggdrasil, is Hell, the source of all corruption. Around Yggdrasil, except above heaven (where it is open to the stars), is a mystical impenetrable curtain of blue flames known as the Weirding Wall.