I would say ninja myself. I'm quite the Naruto fan and the life of the Ninja, no matter how dark seems to have more subtlety to it and perhaps is more strategic and analyctical, generally more N.
Pirates in the romantic sense come across as brash cut throats and murderers who care only for riches. They may have kinship for the rest of their pirate brethern on the ship but ultimately a person who craves power enough to attack merchants and traders would value power and wealth over everything else, and be content to betray or seize power from even close friends.