Terrorists are criminals who use terror (hence their name) and commit flagitious and unforgivable atrocities for religious or political gain, usually varying between "lone-wolf" types to entire organizations seeking to fundamentally reshape society. Terrorists range from ruthless, yet well-intentioned anarchists such as V from V for Vendetta to extremely destructive and genocidal individuals such as Not Important. They can also be hate-mongers, fanatics or simply ruthless individuals who commit mayhem for fun or as an act of retaliation against the society or a law enforcer they hate (e.g. The Joker whom is quoted above).

This is not simply a category for villains who commit large scale destruction; in order to qualify as a terrorist a villain must have a cause beyond their own self gain that they are working for.

Many terrorists believe what they are doing is right (especially those known as Eco-Terrorists), but have no qualms about killing innocent civilians or causing massive damage in order to achieve their goals; in fact, unlike most soldiers, terrorists often deliberately target civilians as they see "terror" as a valuable tool of getting what they desire.

Terrorists can also be linked to other crimes such as piracy, drug-dealing, and slavery, which they may do to fund their cause or as a means to gain more notoriety for themselves.

Sub-Types of Terrorists include:

• Eco-Terrorists who commit terrorist activities for what they see as the good of the environment - this may make them more noble than other villains (at least in their motives) but often they are every bit as dangerous and uncaring of human life as any other villain. Some extreme examples of Eco-Terrorists may also see humanity as so dangerous to the environment that they seek humanity's destruction.
• Bio-Terrorists or Plague-Bringers who spread horrible ailments or extremely dangerous bio-hazards in order to cause fear and panic.
• War Criminals who are guilty of War Crimes (both those convicted and those who managed to evade justice) - usually serving as soldiers or equivalent in their settings they have either abandoned the "code of war" completely or manipulate it in order to justify atrocities that go against the international laws regarding warfare.