Like the narrator in Poe's "The Tell-Tale Heart", the narrator of "The Black Cat" has questionable sanity. In the beginning of the tale, the narrator says the reader would be "mad indeed" if the reader should expect a reader to believe the story, implying that he has already been accused of madness.
The extent to which the narrator claims to have loved his animals suggests mental instability in the form of having “too much of a good thing”. His partiality for animals substitutes “the paltry friendship and gossamer fidelity of mere Man”. Since the narrator's wife shares his love of animals, he likely thinks of her as another pet, seeing as he distrusts and dislikes humans. Additionally, his failure to understand his excessive love of animals foreshadows his inability to explain his motives for his actions.
One of Poe's darkest tales, "The Black Cat" includes his strongest denunciation of alcohol. The narrator's perverse actions are brought on by his alcoholism, a "disease" and "fiend" which also destroys his personality. The use of the black cat evokes various superstitions, including the idea voiced by the narrator's wife that they are all witches in disguise. Poe owned a black cat. In his "Instinct vs Reason -- A Black Cat" he stated: The writer of this article is the owner of one of the most remarkable black cats in the world - and this is saying much; for it will be remembered that black cats are all of them witches. In Scottish and Irish mythology, the Cat Sìth is described as being a black cat with a white spot on its chest, not unlike the cat the narrator finds in the tavern. The titular cat in the poem is named Pluto after the Roman god of the Underworld.
Although Pluto is a neutral character at the beginning of the story, he becomes antagonistic in the narrator's eyes once the narrator becomes an alcoholic. The alcohol pushes the narrator into fits of intemperance and violence, to the point at which everything angers him – Pluto in particular, who is always by his side, becomes the malevolent witch who haunts him even while avoiding his presence. When the narrator cuts Pluto's eye from its socket, this can be seen as symbolic of self-inflicted partial blindness to his own vision of moral goodness.
The fire that destroys the narrator's house symbolizes the narrator's "almost complete moral disintegration". The only remainder is the impression of Pluto upon the wall, which represents his unforgivable and incorrigible sin.
From a rhetorician's standpoint, an effective scheme of omission that Poe employs is diazeugma, or using many verbs for one subject; it omits pronouns. Diazeugma emphasizes actions and makes the narrative swift and brief.