Franklin Harlock is the decendant/alternate reality version of Space Pirate Harlock. Torshiro is the descendant/alternative reality version of himself/the soul of the Arcadia (in series where he never physically appears; this is the explanation). In the various Space Pirate Harlock series/movies/guest appearances it is Harlock who is the main character and Torshiro who is the sidekick. Roles are reversed in Gun Frontier where the main character is Torshiro and Harlock is the sidekick.