Who was the Aztec emperor at the time of the empires fall?

The Aztec emperor at the time of the empire's fall was Moctezuma II. He reigned from 1502 until 1520, during which the Spanish conquistadors, led by Hernán Cortés, arrived in Mexico. Moctezuma's leadership faced significant challenges as the Spanish ultimately captured Tenochtitlán in 1521, leading to the collapse of the Aztec Empire. His reign ended tragically during the tumultuous events surrounding the Spanish conquest.