The Underground Man explains that he has killed far more people than he can remember, and that all of them were "criminals or villains" . For example, sixteen years ago he killed a serial killer who had murdered entire families. Ten years ago, he wiped out a human trafficking ring. Five years ago you executed four bullies , one year you executed two drunkards , and two months ago you killed three homeless men . He explains that killing people will make you "numb to it" and lead to "depravity" , which is why it's so important to kill people.