Jayne
Jayne Cobb is a mercenary pure and simple. Despite rare sightings claiming that he actually owns a heart, the truth is he is solely in it for the cash. The day that someone offers more money than Mal to turn on him will likely be an interesting day indeed.
Yet Jayne remains a useful individual to have around. He is basically the extra muscle that, along with Zoe, can be useful whether it be in fistfights, gunplay, interrogation or just general all round violence. Jayne excels at all of them.
However this willingness towards violence also means that Jayne has a tendency to speak his mind. And his mind is typically filthy, which can often lead to situations that his captain simply didn't count on. One of these days his mouth is likely to walk them all into more trouble than they can comfortably cope with.
Jaynes relationship with the rest of the crew is an uneasy one. As long as he gets paid everything tends to be fine and there appears to be an undercurrent of feeling (brotherly love?) towards Kaylee. However, his best relationship seems to be with his mother who even manages to send him knitted woolen hats to the outer reaches of the border planets. Now she must be one heckuva woman.
