What are the conflicts of "The Cask of Amontillado"?
A conflict derives from a motivation. Whatever makes it difficult to fulfill the motivation is what provides the conflict. The driving motivation in this story is Montresor's desire for revenge. He must induce Fortunato to accompany him into his underground vaults. But this presents many difficulties because Montresor does not want to be suspected of the murder he intends to commit. Fortunato is dressed in a conspicuous costume and even has bells on his cap to attract more attention. The story is largely about the problems, or conflicts, Montresor has with getting his victim down below and chaining him to the wall. The conflict would be the same in any story in which a man wanted to commit a crime and not get caught and punished. I am remindeded of James Thurber's story "The Catbird Seat." It might be said that the confict is about man against man (Montresor versus Fortunato), but it might also be said that the confict is about man against men (Montresor against society). There are many "perfect crime" stories in which the protagonist gets caught. (Poe wrote several, including "The Telltale Heart.) "The Cask of Amontillado" is a "perfect crime" story in which the protagonist/perpetrator does not get caught.
The main conflict in the story is between Montresor and Fortunato. Montresor, our narrator, believes that Fortunato has "inflicted a thousand insults," upon him. It is because of these "insults", which are not named in the story, that Montresor begins to execute his plot for revenge. This conflict would be man versus man, but it is interesting because it seems that Montresor is the only one of the two who is aware of the conflict. Fortunato believes wholeheartedly that the two are friends.
The other conflict we see in the story is man versus self. As Montresor places the final brick into the wall he feels sick for a moment. He tells us it is nothing, but he is an unreliable narrator too. He feels sick, for a moment, with guilt at what he is doing. His revenge plot did not give him the immediate sense of satisfaction he was hoping for and so we see an internal struggle, for but a moment, but it is there.
The major conflicts are revenge and forgiveness. Montresor feels he must kill Fortunato in his lust for revenge. He dreams of the many ways that he can accomplish this, and relishes the idea of Fortunato realizing his death is at the hands of Montresor.
Yet, fifty years later, Montresor is still struggling with his success in killing him. It seems he is showing contrition for his crime, and since Fortunato is dead, it must be that he is pleading to God for forgiveness.