Edgar Allan Poe is obsessed by the subject of death, and there are a number of good quotes on the subject in the book. As page numbers vary from edition to edition of any given book, it might be more useful to you if I tell you where you can find the quotes in their respective chapters. I am using the 1989 Orchard Books edition as a reference.
Poe, or Dupin as he is called, writes about death the first time he meets Edmund. On page 32, or the third page in Chapter 3, he writes,
"Story: Edmund...a boy...missing sister...the sea - bringer of death...abandonment. Release/death...the...necessity...of death...the certainty of death."
On page 96, or the fourth page in Chapter 10, when Edmund asks Dupin if Sis is still alive, he answers cryptically,
"People say I love death. Do you think so? Well, what difference does it make what you think? It takes us all."
On page 120, or the second page of Chapter 13, Dupin enters a room of party-goers, and as he gazes at them, their faces shift and blur into "a single death's-head." He sees the guests as "a gathering of demons, a masque of black death." One of the guests, Dr. Dillard's "orations at funerals are famous ...in Providence," and when Dupin looks at Dillard's wife, he sees "Death's consort."
Finally, on page 204, or the first page of Chapter 22, Edmund tells Poe,
"You never did want to save my sister, did you?...You only wanted to make sure she'd die."
He goes on to tell the man bitterly, in perhaps the most astute quote in the book about death and the man,
"You're always talking about death...but it's living you're frightened of."