In Edgar Allan Poe's "The Cask of Amontillado," Montresor is the main character, as well as the narrator of the story; his victim is Fortunato, who Montresor believes has insulted him in some way. To identify the kind of character these men are, consider the following definitions.
The static character does not undergo any significant change from the beginning to the end of the story. Change does not relate to circumstances, but a change within the character: beliefs, philosophies, etc. On the other hand, the dynamic character does go through a significant change within the course of the story.
Based upon the definitions above, Montresor must be a static character. The fact that he is insane is indisputable: he has planned Fortunato's murder for some time and goes about luring his drunken companion into the catacombs beneath Montresor's house with unfailing purpose. Once there, Montresor gets Fortunato even more drunk than he was when they set out. Montresor displays dark humor and irony when Fortunato states that a cough will not kill him, and Montresor agrees:
“Enough,” he said; “the cough's a mere nothing; it will not kill me. I shall not die of a cough.”
“True—true,” I replied; “and, indeed, I had no intention of alarming you unnecessarily—but you should use all proper caution. A draught of this Medoc will defend us from the damps.
Montresor's stoic demeanor remains much the same until he has walled Fortunato up in a small room he has built, leaving him to die. This makes him a static character. Fortunato is also a static character: the change that he goes through reflects only an alteration in circumstances: he is entombed and sober, but has shown no inner change.
E.M. Forster notes that a round character is realistic, multifaceted, and capable of "emotional and psychological development." A flat character is exactly the opposite: he lacks dimension or depth, but:
...exhibits strong defining characteristics, speech habits, and the like, but still falls short of the complexity of a round character.
With regard to the story, Montresor is not a round character. While he may be realistic in measuring the depth of a madness, once again he is stoic and shows little indication of emotional or psychological depth. For one moment, it seems that Montresor's madness might pass, but it is simply a spark in the darkness of his soul, and he finishes his deadly task:
My heart grew sick; it was the dampness of the catacombs that made it so. I hastened to make an end of my labour. I forced the last stone into its position; I plastered it up.
However, Montresor seems much more a flat character in that he has "strong defining characteristics." When he meets Fortunato, he is cordial. He is manipulative in luring Fortunato to taste the non-existent amontillado by inferring he will ask Luchesi instead. He continually demonstrates a pretense of concern for Fortunato's health. He has planned this murder extensively, and shows himself to be insane—no doubt—but also precise, careful and patient.
Fortunato hardly seems a flat character, showing no strong characteristics, but he also does not exhibit indications of being multifaceted, and he does not show any emotional or psychological development. He may be a stock character, offering no surprises or changes at all.
Are the two main characters (Montresor and Fortunato) in Edgar Allan Poe’s short story “flat” (that is, simple) or are they “round” (that is, complex)? Are they “static” (that is, are they pretty much the same at the end of the story as they were at the beginning) or are they “dynamic” (that is, do they develop as the story progresses)?
Montresor seems reasonably complex. He wants revenge, but he will not openly reveal this motive to Fortunato until he thinks the time is right. He thinks that his revenge will not be complete unless he can make Fortunato aware that the latter has suffered revenge. Montresor therefore plots a fairly complicated revenge. He doesn’t merely push Fortunato off a cliff when the two are alone, nor does he arrange for Fortunato to have an “accident” at someone else’s hands. Instead, Montresor wants to design and carry out the revenge himself, and his need to tell the unnamed “you” at the very beginning of the story about the plot – and about its success – again contributes to our sense of the complexity of his character.
The story would not really need to exist if Montresor were not complex to some degree, and part of the fascination of reading the story involves the chance to “get inside the head” of such a person. Montresor is complex, as well, in the sense that he is capable of deception, of playing a part. He knows how to lie, entice, manipulate, and say just the right things to make Fortunato himself insist on visiting the vaults where he will die. Montresor has cleverly made certain that no servants will be home, and his conduct never raises a single suspicion in Fortunato. Compared with Montresor, Fortunato is a far simpler, less complex character.
Montesor seems a somewhat dynamic character in a special sense. Although his basic plan of revenge does not change, he becomes more and more brazen, more and more self-consciously ironic and risky as the story develops. He also becomes more cruel, and perhaps more mentally unhinged. By the second half of the story he is dropping so many hints to Fortunato and playing so many mind-games with him that Montresor seems more complex in the second half of the story than he had seemed in the first half. Thus, when Fortunato asks to be reminded of the design of the Montresor family’s coat of arms, Montresor replies, without hesitation, as follows:
"A huge human foot d'or, in a field azure; the foot crushes a serpent rampant whose fangs are imbedded in the heel."
Clearly Montresor realizes the appropriateness of this reply, but he confidently assumes that Fortunato is still the same stupid person that he was when he first entered the story. In other words, Montresor correctly assumes that Fortunato, at least compared to himself, is an undynamic character. Fortunato does become a bit more complex and dynamic as he becomes less drunk and as he begins to realize what is happening to him, but he never seems as complex or dynamic as Montresor. The last indication of Montresor’s relatively dynamic and complex nature comes in a single sentence:
My heart grew sick -- on account of the dampness of the catacombs.
Does Montresor feel a momentary twinge of conscience? Is his sickness a fang embedded in the heel of his vengeance? Poe leaves the ending ambiguous, thus contributing a bit more complexity and dynamism to Montresor’s character.