They forced their way into native settlements, slaughtering everyone they found there, including small children, old men, pregnant women, and even women who had just given birth. They hacked them to pieces, slicing open their bellies with their swords as though they were so many sheep herded into a pen. They even laid wagers on whether they could manage to slice a man in two at a stroke, or cut an individual's head from his body, or disembowel him with a single blow of their axes. They grabbed suckling infants by the feet and, ripping them from their mothers' breasts, dashed them headlong against the rocks. Others, laughing and joking all the while, threw them over their shoulders into a river, shouting: 'Wriggle, you little perisher.' They spared no one, erecting especially wide gibbets on which they could string their victims up with their feet just off the ground and then burn them alive thirteen at a time, in honor of our Savior and the twelve Apostles, or tie dry straw to their bodies and set fire to it. Some they chose to keep alive and simply cut their wrists, leaving their hands dangling, saying to them: 'Take this letter' -- meaning that their sorry condition would serve as a warning to those hiding in the hills. The way they normally dealt with the native leaders and nobles was to tie them to a kind of griddle consisting of sticks resting on pitchforks driven into the ground and then grill them over a slow fire, with the result that they howled in agony and despair as they died a lingering death.

It once happened that I myself witnessed their grilling of four or five local leaders in this fashion (and I believe they had set up two or three other pairs of grills alongside so that they might process other victims at the same time) when the poor creatures 'howls came between the Spanish commander and his sleep. He gave orders that the prisoners were to be throttled, but the man in charge of execution detail, who was more bloodthirsty than the average common hangman (I know his identity and even met some relatives of his in Seville), was loath to cut short his private entertainment by throttling them and so he personally went round ramming wooden buns into their mouths to stop them making such a racket and deliberately stoked the fire that they would take just as long to die as he himself chose. I saw these things for myself and many others besides.

...these mortal enemies of humankind trained hunting dogs to track them down -- wild dogs who would savage a native to death as soon as look at him, tearing him into shreds and devouring his flesh as though he were a pig.

And when, as happened on the odd occasion, the locals did kill a European, as, given the enormity of the crimes committed against them, they were in all justice fully entitled to, the Spanish came to an unofficial agreement among themselves that for every European killed one hundred natives would be executed.

"As a result of the sufferings and hard labor they endured, the Indians choose and have chosen suicide. Occasionally a hundred have committed mass suicide. The women, exhausted by labor, have shunned conception and childbirth. Many, when pregnant, have taken something to abort and have aborted. Others after delivery have killed their children with their own hands, so as not to leave them in such oppressive slavery."

The first Spaniards to start fighting suddenly attacked those who were playing the music for the singers and dancers. They chopped off their hands and their heads so that they fell down dead. Then all the other Spaniards began to cut off heads, arms, legs, and to disembowel the Indians.
Bernardino de Sahagun, Conquest of New Spain (1595 Edition)

I resolved to enter the next morning shortly before dawn and do all the harm we could... and we fell upon a huge number of people. As these were some of the most wretched people and had come in search of food, they were nearly all unarmed, and women and children in the main. We did them so much harm though all the streets in the city that we could reach, that the dead and the prisoners numbered more than eight hundred.
Cortes, Letters From Mexico, p. 252-253

The Spanish cut off the arm of one, the leg or hip of another; and from some their heads at one stroke, like butchers cutting up beef and mutton for market. Six hundred... were thus slain like brute beasts. Vasco ordered forty of them to be torn to pieces by dogs.
Conquest of America, p. 141

By other massacres and murders besides the above, they have destroyed and devastated a kingdom... [and] have killed more than four or five million people in fifteen or sixteen years; from the year 1525 until 1540, and they continue to kill and destroy those who are still left, and so they will kill the remainder.
Pedro de Alvarado, An Account of the Conquest of Guatemala in 1524

Marauders by day, offenders by night, murderers of the world.

The Indians are being totally destroyed and lost... They beg with a cross to be given food for the love of God... The soldiers are killing all the llamas they want for no other need than to make tallow candles... the Indians cannot fail to die of hunger.
Hemming, Conquest of the Incas, p. 351

If one were ordered to enumerate the great evils, injuries, robberies, oppression, and ill treatment inflicted on the natives during these operations... there would be no end of it... for they thought no more of killing Indians than if they were useless beasts.
Pedro de Cieza de Leon, The Incas, p. lviii-lix