How do the tones and settings of Poe's stories affect the reader's response to the characters?

Edgar Allan Poe's regular use of darkness and late night
settings is a primary way in which he creates a sense of evil and danger in his short
stories. This is the typical setting in most of his classic tales, including "The
Tell-Tale Heart," "The Cask of Amontillado," and "The Pit and the Pendulum." The
mysterious aura that hangs over these stories helps to create characters who range from
distinctly evil to slightly sympathetic. The fact that many of the characters perform
their reprehensible acts in near total darkness helps to intensify their deviant
personalities, and the reader cannot help but be affected by this as well. Although
several of the main characters in Poe's stories not only narrate but commit murderous
acts (such as Montresor in "The Cask" and the madman of "The Tell-Tale Heart"), it is
hard to sympathize with them because of their deliberate and well-planned crimes. Even
the victims, such as the old man in "The Tell-Tale Heart" and Fortunato in "The Cask,"
are not completely innocent characters; the old man's eye is associated with evil, and
Fortunato has committed unknown crimes against his murderer. Unlike many other stories,
in which the protagonists and antagonists are easily identifiable and are usually more
one-dimensionally good or bad, Poe's characters all seem to possess a touch of
evil--easily identified by most readers.