Seven of Nine is a fictional character who appears in seasons four through seven of the American science fiction television series Star Trek: Voyager. Portrayed by Jeri Ryan, she is a former Borg drone who joins the crew of the Federation starship Voyager. Her full Borg designation is Seven of Nine, Tertiary Adjunct of Unimatrix Zero One. The character Seven of Nine arrived just as the character Kes was leaving, and was intended to introduce a foil to Captain Kathryn Janeway in a similar manner as Spock does to Captain Kirk in Star Trek: The Original Series.