Anti-hero is the term that designates the protagonist who does not possess the virtues traditionally attributed to heroes. Anti-heroes are not inherently evil characters who sometimes engage in morally questionable acts. However, it is sometimes difficult to draw the line separating the anti-hero from the villain.
Noble causes, such as changing the world, even, are commonly associated with traditional Heroes. Anti-heroes might even play the part of a hero from time o time, but it is not what they are precisely.
