First of all, what is a character archetype? In simple terms, it's the epitome or the gist of the type of character you want to embody. Keep in mind that archetypes are just a jumping off point. They can be tweaked depending on the type of story and what the author ultimately sets out to resolve at the end of that story. But what character archetypes do give us is a basic platform to build on the characteristics of a particular character we're going to create.
The archetype being covered today is the anti-hero. What is an anti-hero? The description from several sources I found describe him/her as the unconventional hero. They can display characteristics that are not generally seen as heroic, such as the preference to be a loner, having the tendency to be self deprecating, exhibition of darker personality traits, and/or disregard for common authority. Personally, I prefer these types of heroes to those that glean and shine brightly as they bask in the awe of general society. *laughs*
You can read a more descriptive take here.
Prime examples of anti-heroes:
The anti-hero usually has a warped sense of morals and their actions are fueled by these beliefs that what they are doing is for the greater good. They could also begin as a person who wouldn't necessarily be classified as good at the start of the story, but because of their experiences end up saving the day or making the great sacrifice.
Prime example (and also one of my favorites):
Do you prefer the hero or the anti-hero? Why?