Complete Monsters

The Complete Monster is the worst of all villains, a villain who is pure evil. And for this kind of villain, doing evil for them is as natural as breathing. They can be recognized by these signs:

• They commit acts that are atrocious by the standards of the story, and have crossed the Moral Event Horizon. Villains who have only crossed the MEH once usually do not qualify, although rare examples such as Grand Moff Tarkin if the line they cross is heinous enough.
• They are taken seriously, causing fear, revulsion, and hatred from other characters in the story.
• They are never presented in a positive way.
• They can never feel love for others. If they claim to have love for anyone, that "love" would merely be either perversion, possessiveness, or obsession.
• They are so terrifying, that other villains don't work with them. Although some of these villains work with each other, such as Lord Voldemort and Bellatrix Lestrange.
• Nothing justifies their crimes, and they cannot feel empathy for others and never redeem themselves.
• Unless the protagonist acts, the Complete Monsters will never stop at making the world around them miserable. As long as they aren't stopped, there won't be any happy ending to the story, which is why the heroes must stop these villains at any costs.
• In some cases, simply defeating them is not enough. These villains must be killed. An example of this would be Emperor Palpatine or Scar.