Hernando Cortes along with his men, horses, ships and a few canons set out to conquer Mexico in February 1519 and arrived to Mexico in 1519...
The Arrival
When the Spanish arrived to Mexico they were met by the Aztec tribe, and to their advantage the Aztec looked at them like gods...Cortes decided to meet with the emperor (to get goods) and before heading to inland, he commander all ships to be burnt so soldiers wouldn't back out if they started to get second thoughts.
The aztecs
The Aztecs were a tribe from Mexico, they looked up to Gods and believed that human sacrifices were rituals to please their gods...According to the Spanish, The Aztecs were a very organised tribe and also Mexicans in general, they mentioned their markets and architecture very superior to the Spanish's.
Betrayel
Cortes and his men tricked Montezuma (the emperor) into meeting him, then they kidnapped the Aztec king and threatened him for all his goods (gold, silver) and a way to get out of the capital... they ended up killing Montezuma and all his power to his people...
Escaping
Soon after, the Spanish were surrounded by the people, and managed to fight their way out of the city.
Coming Back...
The Spanish built new ships which he carried overland to siege the city. Many woman and children were killed in the capital...Getting Aztecs by surprise, who weren't used to this sort of battle rather than normal combat.
The siege and its conclusions...
Gardens, buildings, markets, temples and more were all destroyed because of the siege. Health problems and diseases rose like smallpox, and they had no medication and many died as a cause of it. To put it into perspective, an estimate says the population of Mexico went from 25 million to just about less than 2 million!
Religion
As this was mostly caused by the Spanish not agreeing to the Aztecs“ human sacrifices, the Spanish also brutally converted the Aztecs and other tribes into Catholicism and taught them about Christianity.
Who are the Villains?
In conclusion the Aztecs might have done human sacrifices for their religion, but to be fair the Spanish killed many people in this conquer and brutally converted tribes into catholicism causion more then three quarters of the population to be wiped by the siege and the conversion. I would say the Spanish are the villains, even though thats why Mexico speaks spanish today!