Who is the protagonist in "The Black Cat"?

Although most people think of a protagonist as the "good guy" or the hero of the story, a protagonist is simply the main character. I have provided a couple of links explaining what a protagonist is; the first is a literary site that explains the concept in terms of literature only, and the second is just a dictionary definition of the word. 

In The Black Cat, the protagonist is the narrator, and he is certainly not a good guy or a hero. In fact, he is quite the opposite, as he ends up being abusive both to his wife and his pets when he is drunk (which is often), and he ends up killing both his favorite cat and his wife in rather gruesome ways. This narrator is a perfect example of how protagonists are not necessarily always good.