Starzone is the mouse. Zara is the human. Zara uses "Starzone" as a callsign.
The original Starzone was a Biker Mice from Mars fan character done in the usual style of fan characters, she was way overpowered and Mary Sue and may have had stupid random flaws attached to not make her seem as overpowered and Mary Sue as she was. I redeveloped her a bit later and she turned out all right, though I never got around to publishing the fanfic with her and her coterie. I only roleplay her these days.