The Dansker is a quiet old Danish man aboard the Bellipotent that acts as something of an oracle (one who can tell the future or perceive things about the present that others cannot) for Billy. The Dansker served under Lord Nelson on the ship the Agamemnon, and he has a scar to prove it. The narrator notes his "wizened face, time-tinted and weather-stained to the complexion of an antique parchment" (9.3). Though the Dansker's eccentric behavior is too much for some men aboard the ship, Billy reveres him as a "salt hero," and always makes sure to salute him when he walks by.
Billy first goes to the Dansker when he is getting in trouble for stupid little things like storing his hammock away improperly. The Dansker tells Billy, "Jemmy Legs is down on you" (9.9). Billy doesn't believe him, but he won't say anything further. As the narrator notes, "pithy guarded cynicism" was his leading characteristic (9.15). Later, when Billy tells him about the affair with the afterguard, the Dansker takes this as further proof that the master-at-arms is out to get Billy.
As an oracle, the Dansker offers Billy insight into his own problems and a taste of the future tragedy. Yet, either because of his reticence or of Billy's simplicity, he does not give the Handsome Sailor the power to change anything.