Parker
Parker is the Nostromo's mechanic. He is proud of his working-class status in the way that he'd love it if workers revolted against their bosses.
Kind of communistic, in fact. Parker has a big mouth and is not afraid using it. His favorite hobby is to irritate and harass those higher in rank... But when the treath of the alien enters the ship, he turns out to be the 'bad-ass', the hero of the survivors. Parker has guts. He also feels responsible for the rest of the survivors. When Ash attacks Ripley, Parker runs to her rescue. Before the Alien, Parker called Ripley 'bitch' and really didn't like her.