Poe begins the story with a "hook," something that grabs the reader's attention. He notes the thousand injuries and the insult that made him determined to seek revenge. The reader is hooked in a moment of suspense, wondering what the insult might have been and how Montresor will attempt to employ his revenge.
Fortunato's namely sounds and looks quite similar to "fortunate." Poe creates suspense by suggesting that he is going to be fortunate in the end, or that his name is ironic and that he will come to an unfortunate end. But, again, just as Poe does with Montresor's mention of the insult, it is the withholding of information that heightens the suspense. Is Fortunato's name suggestive of some final good luck in the end or is it meant to be ironic?
As they descend into the vaults, Fortunato asks Montrestor about his family's coat of arms. Montresor replies that it is of a foot crushing a serpent whose fangs are embedded in the heel. The motto is nemo me impune lacessit. This means " no one can harm me unpunished." Even if the reader doesn't get the Latin motto, the image Montresor describes foreshadows what he will metaphorically do to Fortunato. Fortunato is the serpent and his fangs are the alleged insult. Montresor metaphorically crushes Fortunato with his heel; this represents his revenge.