The Aztecs brought their many gods and goddesses with them.
As a farming people, the Aztec knew the forces of nature and worshiped them as gods. Most important was their sun god, Huitzilopochtli. The Aztecs also used him as their god of war.
They believed that their 'good' gods should be kept strong to keep away the 'bad' gods. They kept them strong by making human sacrifices.