That was the Aztecs. Incas lived in South America. Aztecs Mayas and Toltecs lived in Central America and Mexico. Aztecs were the ones who did human sacrifice taking the hearts out of living people while they were still beating. They were savage.
You are correct. Mixing the Aztecs and Incas was a silly error on my part.
However, the conquest of the Incas was also much predicated on the effects of disease on the Inca civilization.