We can't quite get our heads around these ghouls. They are an important part of the supernatural cast of characters in this poem, but who or what are they supposed to be? At first they sound like bad news, since ghouls are supposed to be hideous monsters that feed on the dead. Here, though, the speaker calls them "merciful." So maybe they are actually looking out for him. We think this confusion, this feeling that everything is kind of mixed together, is just the way the supernatural works in this poem. It's not an organized philosophy; it's a crazy, chaotic, exciting force.