"Introduce a little anarchy, upset the natural order, and everything becomes CHAOS! I'm an agent of chaos. And you know the thing about chaos? It's fair!"
Villains who are of the Chaotic Evil moral alignment. These villains are violently opposed to any limitations to their own personal freedom and often champion the downfall of society or morality as we know it. Chaotic Evil villains often fall under the "Destroyer" or "Demonic" alignment.
Characters of this alignment tend to have no respect for rules, other people's lives, or anything but their own desires, which are typically selfish and cruel; they set a high value on personal freedom, but do not have any regard for the lives or freedom of other people. They do not work well in groups, as they resent being given orders, and usually behave themselves only out of fear of punishment.
It is not compulsory for a Chaotic Evil character to be constantly performing sadistic acts just for the sake of being evil or constantly disobeying orders just for the sake of causing chaos. They do, however, enjoy the suffering of others, and view honor and self-discipline as weaknesses.
Serial killers and monsters of limited intelligence are typically Chaotic Evil. The Chaotic Evil outsiders are the Demons.
Chaotic Evil is often feared as it is the alignment of madmen, serial killers, zombies, cannibals, and demons. However, this does NOT mean every Chaotic Evil character will mindlessly destroy, but if the opportunity arises for them to cause mischief or harm to others while still furthering their own goals (which are normally personal enjoyment), they will not hesitate to act on it.