What is it about Montresor that makes him an especially effective enemy to Fortunato? Give an example from a book you've read or a film/T.V.
What makes Montresor such an effective enemy of Fortunato is his resolve to get revenge, attention to detail, and ability to act amicably to Fortunato's face while plotting his death. Montresor begins by mentioning he has vowed to get revenge on Fortunato for causing him to suffer a thousand times and laughing at his respected family name. Montresor then elaborates on his feelings concerning the perfect revenge and is careful not to get caught. After carefully plotting his revenge, Montresor conceals his hatred and is friendly to Fortunato's face, which allows him to convince his enemy to follow him into his family's catacombs. Montresor says,
"I gave Fortunato no cause to doubt me. I continued to smile in his face, and he did not understand that I was now smiling at the thought of what I planned for him, at the thought of my revenge" (Poe, 1).
Montresor is also aware of his enemy's weaknesses, which are pride and a love of alcohol. By mentioning that he will consult Luchesi about whether or not he has purchased amontillado, Montresor is able to pique Fortunato's interest and provoke him simultaneously. Montresor also makes sure his estate is empty by lying to his servants, which leaves him alone with his vulnerable enemy. After Montresor successfully buries Fortunato alive, he keeps his secret for half a century, ensuring that he will not be punished for his crime.
The character Iago in Shakespeare's Othello is similar to Montresor in that he carefully plots revenge and feigns friendship to Othello's face. Although he does not directly kill Desdemona, he accomplishes his goal of ruining Othello through manipulation and lies.
Montresor is an especially effective enemy to Fortunato, because Fortunato completely trusts Montresor.
A person could be an effective villain by being supremely powerful or by having some amazing awesome plan. But being an effective villain is made harder, if anybody that you are trying to be a villain toward is always suspicious of you. I imagine that Darth Vader has a really hard time being a sneaky villain. He looks suspicious, sounds suspicious, and has a history of being evil.
Montresor has none of Darth Vader's problems. Fortunato assumes that they are still "buddy-buddy." Fortunato has no previous encounters with Montresor in which Montresor made Fortunato's life miserable. Basically, Fortunato has no reason to suspect Montresor of anything except honesty and good will. And Montresor knows it.
Montresor also knows exactly what to say and offer to Fortunato to get him to follow Montresor anywhere. Montresor name drops "Luchesi" to goad Fortunato. Montresor also knows that the allure of an Amontillado is too great of a temptation to be ignored.
Any episode of CSI would fit the bill for this kind of "bad guy," because in that show the bad guy is always the best friend that you would least suspect. I have a film example. It's the movie "Predestination" with Ethan Hawke. It's based on the short story "All You Zombies." It works as an example because the main protagonist and antagonist know each other completely . . . because they are the same person. There are lots of weird paradoxes in the movie, since time travel plays a big part.