Antihero

This Thunderbolts team is made of Marvel's antiheroes

An antihero is a protagonist or secondary character who lacks the conventional qualities that define a heroic characters.  Often, in superhero stories, this would be applied to characters that aren't quite heroes yet aren't quite villains.  In some cases, they are thought of as superheroes, but are shown engaging in behaviour and/or having motives that differ in the ethics of a traditional superhero.  In others they are thought of as criminals or villains but their behaviour differentiates then from the common villains, as their targets are often other criminals or villains.

Traits of an Antihero

The following is a list and explanation of traits that define or are closely related to antiheroes in comics, These often include...

Willingness to Kill - In most cases, conventional heroes refuse to kill or will only do so as a last resort.  Many antiheroes are often willing to kill their enemies and in many cases even when an enemy could be taken alive.

Willingness to Commit Crimes - In many cases, antiheroes are willing to commit crimes to accomplish their goals.

Differences Between Superheroes and Antiheroes

Though a superhero can be an antihero, often certain distinctions are made to show how has antiheroes have a different set of ethics than the average superhero.

Willingness to Kill - In superhero fiction in general, superheroes don't kill or only do it as a last resort. Most antiheroic characters are more willing to commit lethal acts as a method of stopping evil.

Motivation - While superheroes generally are motivated to make the world a better place and save lives, often antiheroic characters in superhero fiction tend to be different.

Relationships Between Superheroes and Antiheroes

In most cases, the relationship between a more traditional hero and an antihero is strained at best.  In many cases, depending on the nature of the antihero, a superhero may work as actively to stop an antihero as they would a villain.