The one thing that most agree on is that when Viracocha (Inca Supreme Deity) created the earth, the first people there defied him, so he flooded the earth, leaving only two people alive, These two people he had kept in a box to be safe. He then forgave the two survivors and sent then back to earth after the flood. He then made other people out of clay, and made the sun and the moon for light.

  This flood idea is in a lot of other religions and regions in the world, so I did a little research, if you would like to know more click here

With this idea of creation, there are three main ideas as to how the Inca people became who they where.

1.    This version talks four bothers and sisters coming from Paccari-tambo (Inn of origin) 20 miles from present day Cuzco. These brothers and sisters looked different than the common people of the time, which gained them power. The four brothers and sisters moved toward Cuzco in search of a good place to settle. One of the brothers Ayar Cachi, climbed to the top of a mountain, Huanacauri, and threw rocks down at the neighboring hills and created ravines, where no one had been before. The other brothers pushed Ayar Cachi to go back to the caves from where they came to get some objects that they had left behind. Once Cachi was in the caves the other brothers walled him inside. The other brothers went on to make a settlement at Tambu Quiru. Here they where visited by the spirit of their brother, who told them to go farther on to Cuzco. Then the spirit turned itself to stone on Haunacauri. Then, the other brothers pushed Ayar Cachi to go back to the caves from where they came to get some objects that they had left behind. Once Cachi was in the caves the other brothers walled him inside. The other brothers went on to make a settlement at Tambu Quiru. Here they where visited by the spirit of their brother, who told them to go farther on to Cuzco. Then the spirit turned itself to stone on Haunacauri. Ayar Manco (Manco Capac) went on with the sisters, until they reached Cuzco. There they found that the area could meet their needs, and Ayar Manco and Mama Ocllo became the first rulers.

Small Fact: The thought of people coming from rocks is common South American mythology.

2.    The son God, Inti, could see men primitively, this made Inti pity the men. Thus he sent two of his children Manco Capac     (Ayar Capac), and Mama Ocllo to lake Titicaca so the siblings could teach man how to live a civilized life. Before teaching the men of civilized life, the siblings had to find a good place for the men to settle. They did this by using a golden rod, sent down from there father, with the instruction of settling where the rod would could be buried entirely in the soil. When they reached Cuzco valley, they stopped at Huanacauri, there they decided to move further into Cuzco, where the rod could fully be buried in the earth. They won the people over by teaching them the arts of civilized life, thus making their empire.

3.    In this version Inca divine Kingship was a deception of the people. An arrogant king would parade through the city clad in a cloak of gold and beads. The people where so impressed by him, they worshiped him and his offspring as offspring from Inti. 

Some other theories:  Some say the first Inca king was Manco Capac Others tell the story of Sinchi Roca. The tale explains how he came into power because his mother say that the Sun was about to send a rule to them. Then she birthed her child in the mouth of a cave, dressed in brilliant clothing. The people gullibly accepted the son, Sinchi as  their king.

Inca Worship:

Inca's worshipped their dead, culture heroes, nature, many different Gods and Goddesses, and their king, who was thought to be a descendent of Init the Sun God. The Inca's would worship in various ways, thought festivals, dancing, music, and sacrifice. Sacrifices usually consisted of plants, minerals, and fabrics. Live Animals, and humans where only done in extreme circumstances. The Incas where very spiritual they consulted oracles for just about everything, for example, illness, crime punishment/conviction, and what to sacrifice.

Death and the After life:

The Inca usually mummified their dead, mostly the kings, and priests. (Cool interactive way to show the layers of Inca mummification http://channel.nationalgeographic.com/channel/inca/)  They would leave things from the persons life with the dead because the Inca believe that people had two souls. When you died one soul would go to it's rightful place, usually Uca Pacha an underworld type place that is dark, cold, and you are eternally hungry or Hanan Pacha, a paradise, only for the souls of the just. The other soul stays with the body, which is why things are placed with the body. These things are usually what a person may need, or something that a person may have been very close to.

The Inca also had three aspects of the world, Kay Pacha which is the Present, Uku Pacha which is the past, and Haunan Pach, The future/ supra  world. Mortals can enter these world, though each world is inhabited by spiritual beings.  

Worker uncovering Inca dead in the town of Tupac Amaru