An unnamed man who describes his youth as being marked by a gentle disposition and a deep fondness for animals. As he matures, he develops a severe dependence on alcohol, which drastically alters his personality. He transforms from a loving husband into an erratic and violently unpredictable figure. He frequently blames his shifting temperament on an uncontrollable spirit of perverseness.

The narrator's spouse is a caring woman who indulges her husband's fondness for pets by filling their home with various creatures. She holds a passing belief in folk superstitions, specifically noting the old notion that black cats are witches in disguise. Her consistently compassionate nature contrasts sharply with her husband's deteriorating temperament.

Pluto is a large and highly intelligent black cat. For years, he acts as the narrator's most loyal companion, following him around the house and through the city streets. As the narrator's alcohol dependence worsens, Pluto senses the shift in his owner's demeanor and attempts to avoid him, which only invites unwarranted hostility.

A mysterious black cat closely resembling Pluto, except for a large patch of white fur on its chest. The creature demonstrates excessive affection toward the narrator, following his every footstep. This unwavering devotion causes the narrator immense distress, prompting him to avoid the animal out of a growing sense of dread.