18. River Tam
Appeared in: Firefly, Serenity Maybe we love cliches a little too much, but mysterious bad-ass girl running from her past who happens to be gorgeous in a dangerous sort of way gets me every time. And so we have River Tam to talk about. River was sort of the driving force behind the mythology of Firefly, the big mystery of the show. Who was she, what was she, where did she come from. That sort of thing. She was semi-functional at times, clearly disturbed, and had only her brother as her keeper. What was so great? Her depiction by Summer Glau was fantastic, winning the actress several awards for both Firefly and Serenity. Her background, or lack there of, got viewer's brains working, though thanks to the early cancellation of the show, we didn't get as good of an explanation as we might have - but River was a big focus of the Firefly crew's big screen adventure, Serenity. River, who was almost always barefoot in the series, seemed like a feral child - but one with incredible power.