What source are you using in quoting all of these casualty figures relating to the Mongols? 100 million? Who did the tabulating at the time? The Germans were meticulous in their record keeping, it’s part of what got them hung in the Nuremburg Trials. Although they were blood thirsty, it was my understanding that the Mongols moved fast and were more interested in loot so much as to just wanton slaughter. In the modern era, nothing can compare to an entire Western European nation, considered one of the most enlightened , Christian and ‘’civilized’’ as Germany doing what it did.
The Mongols reopened the Silk Road, and they preferred to collect taxes than conduct wars ~ I doubt the Mongols came anywhere near 100 million victims ~
But the Mongols did kill many, however Weatherford in Genghis Khan and the Making of the Modern World states that conservative scholars place the number of dead from Genghis Khans invasion of central Asia at 15 million within five years, however even this more modest total would require that each Mongol kill more than a hundred people.
The Chinese censuses show a drop in population from 100 million to 70 million in 1290s and 60 million in 1393 a drop of 40 million.
However, perhaps many were due to the spread of the plague? and due to the flooding of the yellow river with the famine it brought?
Let's assume they did kill 40 million - that was 9% of the world population!
They were not interested in loot per se but did believe they had a divine cause to attack the city dwellers and bring them to the pure ways of nomadism -- remember that Genghis Khan made a rule for his successors to live in yurts only, not a settled life