But who was to populate this newly formed world of the Fifth Sun? In the account given in Leyenda de los Soles the task of creating humanity was given to Quetzalcoatl, who was to descend to the underworld to find the bones and ashes of those who had died in the past suns. From these he would "recreate" humanity. After using his shrewdness to overcome many obstacles along his journey, Quetzalcoatl was finally given the impossible task, by Mictlantecuhtli, the lord of the underworld, of sounding a trumpet shell that had no holes in it and therefore could not be blown. With the help of worms who made the holes for him and bees that flew inside to make the shell sing, Quetzalcoatl passed this test. Then Mictlantecuhtli reluctantly gave him one long bone , only to change his mind and pursue Quetzalcoatl with his demons to get it back. Running in flight, Quetzalcoatl dropped the bone, causing it to break into many pieces, thus accounting for the small stature of humans. But he gathered the pieces, made his way back from Mictlan, and gave the bones to the woman called Cihuacoatl, perhaps Quetzalcoatl's consort, in Tamoanchan, who ground them into a kind of flour. Making a dough from this, she put it into a womblike earthen receptacle into which first Quetzalcoatl and then the other gods bled their penises in a ritual of autosacrifice. In four days a male child, Oxomoco, appeared, and four days later, a female, Cipactonal; together they became the parents of a new humanity. . .
Markman 1992:76-77
According to the myths, however, humankind, the population of the Fifth Sun, is destined to meet its end by being devoured by celestial monsters, the survivors to be destroyed by earthquakes. The logic of the myth suggests that there could never be a sixth sun because the Fifth Sun is the synthesis of the quadrants of reality and their qualities as well as a synthesis of the other four suns and would therefore not be subject to the great law of continuous change through destructive catastrophe. The world must end "forever when the structures which confer sense, meaning and order on reality no longer apply." Accepting the prediction literally, the Aztecs were prepared for horrendous events to take place at the end of every fifty-two-year cycle, when the calendar systems had run their full course and the new cycle had not yet begun. This was a liminal interval, a dangerous interlude betwixt and between the old life and the creation of new life, a perilous moment of nonexistence. Either the new cycle would begin, or it would not. In this "no time," this period of limbo, all fires were extinguished, pregnant women covered their faces with maguey leaves and were locked up or carefully guarded lest they change into beasts that could devour mankind, sacrifices were made, and the priests anxiously watched the heavens for a sign--the movement of the star we call Aldebaran past the "middle" of the night sky--that the new cycle had begun and the danger had passed. This was the most critical of moments, the point in time at which it would be determined whether the Fifth Sun, the center of all reality, was to be the end of time itself or whether it would continue as "the navel of the earth," the continuing source of all creation.
Markman 1992:77-78
The Tree of Origin, from the Codes Vindobonensis
...
Following the detailed interpretation of this image by Jill Furst, we see a tree with a cleft in its crown from which emerges a nude male covered with red body paint. A nude female stands above him. On either side of the tree, identified by their signs, appear 7 Rain on the right, holding a cutting implement in his right hand while touching the tree with his left, and 7 Eagle on the left side, holding a clawed implement in one hand and similarly touching the tree with his other hand. They seem to be cutting into the trunk of the tree, which appears to grow from a feathered carpet, a Mixtec symbol for a plain. At the base of the tree there is a female head with an extended tongue, a fang in the corner of her mouth, and long hair with what appear to be red "bangs," both probably generative signs, the color suggesting one of the possible colors of corn. Together with the male figure at the top of the tree, this female figure at the base indicates the male-female nature of the birth tree, a metaphor similar to the male-female nature of the Aztec creator god, Ometeotl. The blue tubular earplug she wears is a male characteristic and thus suggests again the dual sexuality of the tree, as does the fact that the left side of the tree has a row of white circles--female symbols--while the right side has three arrows--masculine symbols--increasing in size toward the bottom. The body of the tree itself is swollen, idicating perhaps that the offspring will be removed by cutting into the "pregnant" trunk, which is divided on top by a v-shaped cleft before being separated in half vertically along the center by a thin red line that thickens as it reaches the bottom. {another interpretation}
Markman 1992:153
Xiuhtecuhtli and the Four Directions from the Codex Fejervary-Mayer
The arms of the Maltese cross represent the spatial dimension of the created world; they are the four cardinal directions, each having its sacred tree topped with its particular bird. Gods or Goddesses stand on either side of each tree, and the quadrant of each direction is bordered with its representational color. At the center of the quincunx, and thus at the center of the cosmos, the the fire god Xiuhtecuhtli, armed with spears and the recipient of four streams of blood. The quadrant at the top of the diagram represents east and the gods Itztli (Flint Knife) and the sun as Pilzintechutli (Young Corn). In the quadrant on the left representing south we find Tepeyollotl (Heart of the Hill) and Tlaloc (Rain), while the bottom quadrant, west, contains the two goddesses Chalchiutlicue (Skirt of Jade) and Tlazolteotl(Earth). The remaining quadrant, representing north, contains the corn goddess Cinteotl, and Mictlantecuhtli, lord of the underworld. In addition, some scholars see the body parts--hand, ribs, leg, and head-- of a dismembered Tezcatlipoca in the four corners. The spiked disk in the east represents the sun rising in the east, with the north and south on either side and facing the west, where it will come to rest, symbolized by the head of death, suggesting its disappearance in the underworld. It has also been suggested that the spatial division corresponds to the four divisions of the city of Tenochtitlan and that from each of the four cardinal points sacrifical blood flows toward the ceremonial center, representing the "nourishment" that will enable the gods, that is, the world of the spirit, to continue to maintian life in this world.
Markman 1992:167