I think it's captain/baron but baron are like soldiers "with land" so they also have title. All I know for sure is dregs get their arms torn off to signify they're low born, and humiliate them. Dregs and vandals try to prove themselves to the higher nobility to be raised in rank. Maybe a dreg and vandal can only go to captain, unless they do something great and they can become a baron.

If I'm not mistaken its barons run skiffs (smaller fallen ship that you see all the time) and kells have ketchs the enormous ship that fly's in during extraction crew public events