When the Aztecs settled down on the magical island that had appeared at "The Place of the Prickly Pear Cactus", they did not go to war, as they usually did. They still had to feed their hungry gods, but they used their own people instead of captives. That's what their god had told them to do. (Actually, according to Aztec legend, their god had told them not to go to war for a while, as they needed to built up their strength.)
After a while, the Aztec emperor sent a messenger to a nearby tribe, inviting the chief's daughter to visit the Aztec capital, and meet his son. His invitation was accepted. The princess of the nearby tribe arrived at the capital city, with many servants and many presents for the royal family. She was delighted to meet the emperor's son. They had a lovely dinner together. By the end of the evening, she was more than willing to become his bride.
A few days later, her father arrived in Tenochtitlan, the Aztec capital city. He expected to discuss would goods his daughter would bring to her marriage with the emperor's son. That's when he heard that his daughter and her many attendants had been sacrificed to feed the many hungry Aztec gods. In fact, he probably would have been sacrificed himself, only fortunately for him, he had traveled to the city with many armed guards. The emperor tried to explain that it was an honor to be sacrificed. But the chief would have none of it. He hurried home to his people, and the very next day sent his army to destroy the awful Aztec people.
As their god had told them to do, the Aztecs had taken time to grow in strength before they had contacted this nearby king. Their young men had become capable warriors. They had many weapons. They won easily. The Aztecs demanded tribute in the form of jewels, food, clothing, and of course captives to feed their hungry gods. That made the Aztecs very happy. The Aztecs went on to conquer other tribes in the area. That made them very rich.