Serial Killers include villains who personally killed at least three people. They usually have "cooling off" periods in which they won't commit any murder.

Serial Killers include:

• Psychopaths who are driven to kill by madness.
  • Although almost all serial murderers qualify as psychopaths, these characters are by essence chaotic and often kill for no other reasons than the thrill of doing it. They can also be vengeful for an event in their life that drove them crazy (a featured example: Benjamin Willis better known as the Fisherman).
  • These villains are shown to be expert liars and master manipulators, and in many cases they are also seductive. They have a seemingly normal life when not engaging into murder. They may be obsessed with a certain topic or target a specific group of people and usually kill their victims in similar ways.
  • They often act alone, because they are usually paranoid and do not put trust in their entourage or relatives. Though it is possible for Serial Killers, especially if they are close friends, lovers, or relatives (even whole families), to team up in order to murder strong foes or cause more mayhem.
  • Examples: Billy Loomis, Freddy Krueger, Mai Mashiro, Edward Nygma (of Gotham), Esther Coleman, Deacon Frost, Aria and her parents (of Akame Ga Kill!), Francis Dolarhyde and Amshel Goldsmith.
• Assassins (include murderous ninjas as well). Unlike psychopaths, they are not always deluded or crazy, though many can be insane or extremely sadistic. Examples may include various incarnations of Deathstroke and Aurra Sing.
• Tyrannical characters who oversaw the death of many, usually opponents or freedom fighters. Example: Emperor Mateus, Judge Claude Frollo and Esdeath.
  • They can be Disciplinarians who use the capital penalty as a mean of coercion.
• Terrorists who led a deadly attack in a place, usually resulting in the death of many innocent people.
  • Worse, they can be Destroyers who kill everyone in their way when they are rampaging. Examples: The Crusader (also known as Not Important) from Hatred.
• Cult Leaders (usually satanists) who sacrificed many people over the years. An example: Margaret Holloway.
• Some violent vigilantes. Examples: Dexter Morgan or Rorschach.
• Some demons or Youkai who, once summoned, will commit multiple murder because it is in their inherent nature to kill. An example: Lucius Wagner.
• Protective villains or In Love villains who killed several people in order to protect or revive someone. Examples might include most characters who fit the "yandere" archetype (e.g. Yuno Gasai or Yandere-chan of the upcoming game Yandere Simulator).

Serial killers are much more dangerous than Murderers who killed only one or two people as they are more experimented and competent or alternatively less remorseful than Murderers.

Do NOT include generic Cataclysmic villains (e.g. Frieza or Abraxas) who butchered without distinction entire worlds, galaxies, universes or even realities, as this category is meant for villains who target individuals. (Such villains can still qualify if, aside destroying worlds, they also have killed multiple individuals who stood in their way.)

Also, do NOT add villains already under Murderers to Serial Killers or vice versa. Being a serial killer disqualifies the villain from a simple Murderer. In addition, Serial Killers do NOT necessarily have to be Pure Evil unless they have the intent on claiming other lives in a gruesome manner.