A villainous protagonist is a character who is the central focus of a story, yet does not have the traditional "heroic" qualities of a classic protagonist. In short, these are the villains who are the main characters of their own stories. Should they have heroic qualities, the audience commonly nickname them "anti-heroes".

There can be more than one villainous protagonist in a same story, but each one has to share the same amount of screen time in order to qualify. In video games, any playable character(s) can qualify (e.g. Michael De Santa, Franklin Clinton and Trevor Philips, who are the protagonists of Grand Theft Auto V).

Also, former protagonists who became antagonists (usually due to a tragic event in their life) can also be included, given that they played a large part in the story, even if they no longer function as heroes.

Such characters can be found in every fiction, though they are quite uncommon in fictions destined for kids since these works' protagonists usually convey values that are moral.

Some can be falsely seen as the "protagonist hero" as he/she is seen on the cover of the movie/book and there for the reader/watcher are being lured to believe that the character is the main hero of the story, while they are in fact the main antagonists. One example is Major Chip Hazard from Small Soldiers.

These characters are rarely Pure Evil, because it is very unlikely and odd for a leading character to actually be that evil. In addition, protagonists that are villainous usually set the villainy standards in their story. However, protagonists can still be Pure Evil if they have no redeeming qualities and if the surrounding characters are visibly distressed or repulsed by their actions, thus meaning that they stand out from the rest (e.g. Patrick Bateman, Louis Bloom, Frank Underwood, The Crusader, Light Yagami, Richard III and Henry Lee Lucas). In addition, horror works and exploitative medias often feature purely evil protagonists who are meant to be feared as mascots of their own franchise (e.g. Freddy Krueger, Chucky and Alan Yates).