Montressor and Fortunato are the primary characters. The setup for predator and prey begins in the first line:
"The thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge."
We learn our villain's name for the first time close to the end, when Fortunato, cries out, "For the love of God, Montressor!"
There are no other characters directly involved; Fortunato and Montressor are completely alone. However, in order to lure Fortunato into the catacombs, Montressor engages in some name dropping, mentioning Luchesi, a wine connoisseur. He tells Fortunato:
"As you are engaged, I am on my way to Luchesi. If any one has a critical turn, it is he...".
"Luchesi cannot tell Amontillado from Sherry."
Another indirect reference is also issued from Montressor, who alludes to the greatness of his own family:
"The Montresors," I replied, "were a great and numerous family."
Other indirect characters are the Masons, a secretive, exclusive sect. Fortunato is a member:
He laughed and threw the bottle upwards with a gesticulation I did not understand.
I looked at him in surprise. He repeated the movement - a grotesque one.
You do not comprehend ?" he said.
"Not I," I replied.
"Then you are not of the brotherhood."
"You are not of the masons."
"Yes, yes," I said...