I don't really have a worst nightmare... some of my more vivid dreams do take place in a land of fire and death, but its more dark fantasy-ish than nightmare-ish. (And I often have all sorts of cool powers). With that in mind, I suppose I'll bring along my Dervish from Guild Wars. He may not be the most social guy, but he's bested just about every sort of demon and monster you can think of, with a dark god thrown in for good measure.