What characteristic was respected by the Aztecs; it helped them become leaders.?

In part of being advanced both socially and technologically when compared to other early civilizations, it was arguably their ruthlessness that led them to dominate. Their routine human sacrifices hinted at their savage military, as they would offer daily sacrifices from the enemy population. They were relentless and thirst for expansion, and their need for human sacrifices and slaves drove them to do so. Ironically, their fall was the result of European invasion. Though their deaths were mostly due to the European diseases they had brought, the Aztecs had went down the same path that they forced onto those who were conquered by them.

Note:

This question seems to be subjective, rather than looking for a specific answer, so try to paraphrase my response lol.