I like to point out two things about the Conquistadors.
The first is that these were hardened mercenary soldiers who had fought in very brutal wars in Europe, but when they saw what the Indians had done and were doing in the New World, they were convinced to a man that this had to be utterly destroyed as evil beyond evil.
The second was of a Catholic priest, a scholar who went with them, ordered that they not destroy the Aztec library of scrolls. He wanted to review and report on their contents to the Vatican for any historical or cultural value within.
After he reviewed them, he found their contents to be so grotesque, profane and inhuman, that he personally ordered them destroyed and oversaw their destruction. So only a few scrolls kept in other parts of the region still exist.
Smart priest. I think the Aztecs were more evil that just about any fictional evil realm of science fiction or fantasy. The fact that they made it work, just made it scarier. Whenever I look for a model of evil, I skip over Nazi Germany to the Aztecs...