Gods
The Aztecs were polytheistic, meaning they believed in many gods. There were over 1,000 gods that the Aztecs believed in, but the main ones were Ometecuhtli and his sister Omecihuatl that represented the forces of nature and duality, Quetzalcoatl the creator of modern day humans and the wind god, Huitzilopochtli the warrior sun god, Xipe Totec the season god, and Tlaloc the rain god. Gods were extremely important to the Aztecs and their daily life. The Aztecs even sacrificed other people for them. Legends say that Montezuma II sacrificed 20,000 people after a massive battle against their enemies.
Sacrifices
The Aztecs believed in human sacrifices. The Aztecs believed they had a "blood-debt" to their gods. This meant that they had to sacrifice things in order prevent disasters, or that the sun would still rise every day. Humans were a very common sacrifice to the gods. The people being sacrificed were not always Aztecs, often times it was a prisoner captured in a battle. Every month they would paint the person being sacrificed. Then climb the temple to a large stone slab where the person would lay down. Next a special priest would cut out the heart and hold it up to the sun. Then they pushed the body down the stairs. It has been estimated that thousands of people if not more were sacrificed each year. Human sacrifices were not always the only type of sacrifice though. There were blood-letting sacrifices where a person cut themselves to offer their blood to the gods. Animals were also sacrificed.