Speaker
The only character in the text of "Wild Nights - Wild Nights!" is the speaker. While the reader might imagine the speaker as Dickinson herself, the lack of dedication seems to plant the poem rather firmly in the realm of the imagined. The speaker is a lover addressing their beloved. Their tone is both ecstatic and nervous, an impression only deepened by the intensity of the images they utilize. As the poem progresses, this tone becomes magnified by an increased use of dashes. They also end multiple lines in exclamation points.
The Beloved
Interestingly, the beloved is never actually depicted in the poem. They are referred to only in their absence and in the abstract, idealized as the source of both solace and tempestuous passion. The speaker seems only capable of imagining their love interest by describing the uncertainty between them and the joy of their potential union. Beyond that, no description of the beloved is offered.