Who is Montresor addressing when he says "You, who so well know the nature of my soul"?

I believe there is substantial evidence to suggest that Montresor is speaking to a priest. First, he says that this person "so well know[s] the nature of [his] soul," and a person to whom he has made confessions to for many years would certainly understand the nature of Montresor's soul. The purpose of confession is to reveal one's sins to one's priest and be absolved of those sins, and so it makes sense that Montresor would be speaking to a priest now. In the last lines of the story, he says that for a "half of a century no mortal has disturbed" the bones of his enemy Fortunato. This means he committed this murder fifty years ago. If Montresor was in his thirties when he committed the murder, that means he is in his eighties now. He apparently has not revealed this crime to anyone before now and we might imagine that he reveals it, just prior to his own death, to a priest who can absolve him. I have heard some suggest that he might be speaking to a family member, but I believe I am persuaded that he speaks to a priest given his own word choice and the timing of his confession.

It has been suggested that Montresor is confessing to a priest. It has also been suggested that he is writing a letter to a friend. There are other possible answers to the many questions about the identity of "you, who so well know the nature of my soul."
One of them is that "you" means you, the reader. This puts you close to the narrator. It also makes you an accomplice, because you know where the body is buried. You are to imagine that you have known Montresor all your life and that he is confiding in you because you are the only person he can trust with his guilty secret. By the time you finish reading this tale you will indeed know the nature of his soul very well.
Another possibility is that Montresor is addressing a totally imaginary confidante, or perhaps a private diary.