In the first two stanzas, the only character appears to be the speaker, who refers to himself frequently as "I" as he (or she) imparts his wisdom about life. In the third, stanza, however, we realize he is addressing someone or something he feels close to, asking,

Of those so close beside me, which are you?

Later, he refers to "you and me" and addresses the other entity as "lovely." (Note that "lovely," as is often the case in poetry, can have more than one meaning in this context.)

Other characters are God and nature (called "Great Nature"). The poet pays special attention to nature, mentioning the Ground and the Tree, capitalizing them as if these were names of specific beings. He also notes the worm.

Roethke is careful not to give any specific characteristics to the speaker or the one he addresses. We know nothing about either of them, except that the speaker loves the natural world. It is left to us to ponder if the addressee is a living person, a ghost of someone who has died, or a part of nature. In this way, Roethke keeps the reader's focus not on character but on the universal themes he is exploring. His speaker is an Everyman (or woman), and all of us too can follow his path of moving slowly and with great alertness, learning by going "where we have to go."