Cortez & his small army were adored by the vast majority of native Americans in the central Mexico area. They HATED the Aztecs and saw Cortez as their savior. It was Native Americans that wiped out the Aztecs, not the Spanish.
After that Spanish & Native Americans married and produced several generations of what we now call 'Mexicans'. Unfortunately, Europeans, who had absolutely no knowledge of microbiology, brought diseases that Native Americans had no anti-bodies to fight. Those hybrid Spanish/Natives that inherited the immune systems of the Spanish lived, those that did not died.