According to Christopher Hudson, regarding Genghis Khan,
On one occasion, his lieutenants were idly debating what was the greatest enjoyment that life afforded. The consensus was leaning toward the sport of falconry – Genghis owned 800 falcons – when their leader offered his own deeply felt view.
“The greatest pleasure is to vanquish your enemies and chase them before you, to rob them of their wealth and see those dear to them bathed in tears, to ride their horses and clasp to your bosom their wives and daughters,” he announced.
Genghis and his hordes annihilated every community which resisted them, killing or enslaving men, then distributing captured women among themselves and raping them.
“The plundering of enemy territories could begin only when Genghis Khan or one of his generals gave permission,” wrote Russian historian George Vernadsky.
“Once it had started, the commander and the common soldier had equal rights, except that beautiful young women had to be handed over to Genghis Khan
After analysing tissue samples in populations bordering Mongolia, scientists from the Russian Academy of Sciences believe the brutal ruler has 16 million male descendants living today, meaning that he must have fathered hundreds, if not thousands, of children.
According to Political Ponerology
Inherited and acquired psychological disorders and ignorance of their existence and nature are the primal causes of evil. The magic number of 6% seems to represent the number of humans who either carry the genes responsible for biological evil or who acquire such disorders in the course of their lifetime. This small percent is responsible for the vast majority of human misery and crime, and for infecting others with their flawed view of the world.
If everyone were evil, society would be impossible. 6% is probably about all it can tolerate. For examples of the absurdities that follow from ignoring this evolutionary balancing act, see this review of Sex and War.