In the case of a lyric poem such as "Thanatopsis," we're of course not speaking literally of "characters" as in a story. So the characters, such as they are, have a metaphorical existence in some sense, but as we will see, there is also something very materially concrete about them.

The speaker is always a "character" in a poem. In this case, the speaker reviews the fate of mankind after first extolling nature. He counsels that one should not fear death but rather should take heart in the fact that by dying, we are both becoming part of nature, merging physically with the earth and simultaneously being united with the millions upon millions who have died before us, entering into the great "place of death" (thanatopsis) that the earth is.

Thus, those already deceased are "characters" in the drama. It's startling to contemplate the vastness of this tomb of earth, in which the remains lie of every single being who has existed since the birth of the earth itself. One of the remarkable things in Bryant's poem is that this point he makes—that earth is in fact a gigantic tomb—is one that most of us have little consciousness of, though it's so obviously true. In a way, the lack of awareness is analogous to the usual human attitude to death itself. Both death and the mass tomb of earth are basic, incontrovertible facts, yet we implicitly act as if we are somehow not to be affected by them or to become a part of them.

Last is the "character" earth itself. In Greek mythology, Earth (Gae) is the proto-goddess who is the mother of all beings. This notion of earth-as-mother is implicit in "Thanatopsis"—in other words, that by dying we return to where we came from. But the symbolism goes further in that we have, of course, never actually left the mother. The extolling of nature through the entire poem is a metaphor for the essential "goodness" of death. Just as the contemplation of nature comforts us in life, so will our merging with nature fully, in the end, be like the experience of one who "lies down to pleasant dreams."