Black Sun (mythology)
The Black Sun in Mesoamerican mythology has many mystical meanings, among them it is connected to the god Quetzalcoatl and his penetration in the Underworld through the west door after his diurnal passage on the sky. For the Mexicas there were two suns, the young Day Sun and the ancient Dark Sun. Some scholars regard the mythological Black Sun as the ancient female origin of all, it is both tomb and womb. This way, it is the oneness that uniformly integrates unawareness, death, and yet an expectation of fecundity.
The Aztecs associated the passage of the Black Sun, on its nightly journey through the underworld with the image of a butterfly.The butterfly, in turn, is an archetypical symbol of the transcendent soul, transformation and mystical rebirth, whereas also seen in the figure of the frightening earth goddess Itzpapalotl, the "Obsidian Butterfly," that devoured people during the solar eclipses, while the Aztec underworld was the eternal dwelling place of the souls. According to the Codex Ríos, the underworld was made of nine layers. The first level was the Earth's surface, which also had the entrance, or the face of a gigantic toad that devoured the dead and gave access to the other eight lower levels. The souls of the dead occupied the ninth level known as "Mictlan Opochcalocan."
The connection with nocturnal elements is also ascribed to the god Tezcatlipoca, son of the primordial god Ometeotl who was a god of dualities such as light and darkness. Black Tezcatlipoca, as he was known, was one of the Five Suns of the creation myth of some Nahua peoples; he ruled over the north, the Earth, night, sorcery, and judgment. Another interpretation  holds that the sun god Huitzilopochtli crossed the underworld during the night bestowing light to the forgotten souls, however, he demanded human blood as payment to his tasks. Before his nightly effort, Huitzilopochtli was accompanied from zenith to setting by the Cihuapipiltins, the souls of women who had died in childbirth, which then reappeared as crepuscular moths on Earth.
Sculpture of a Teotihuacan feathered serpent, a forerunner of Quetzalcoatl, at Museo Nacional de Antropologia in Mexico City
At archaeological scenes, the Plumed Serpent shows a man with a black sun within a yellow sun. In this manner the spinning of the sun and black sun shows a wheel crossing with an obfuscatory motion where four black rays move out of four yellow rays. According to some authors, these sets of four rays relate to the four cardinal points and the four quarters, they represent the governance held by the gods over the human race since its infancy, as well as the annual rotation of the heavens, and the universal rulership portrayed in the great dance called "Mitotiliztli," which reproduces the appearance of a wheel.