We just got turned on to Firefly at a con and spent the past two weeks going through the DVDs. It's going to be horrible to wake up tomorrow and realize we have to wait until April for more Firefly. But being the kind of role-playing geek I am I'm contemplating the crew and trying to decide who's a PC and who's an NPC.
River's the easiest--she's the dependent NPC for PC Simon. Sure, she's got tremendous powers but they appear by GM whim, not when it's useful for the players. And Simon has to go through all sorts of work to take care of her, so she's clearly a dependent. The powers are just plot hooks for the GM to use later.
Mal is a PC with Kaylee as his dependent. He gets to make decisions and have adventures off-ship. She stays on the ship and still gets shot, tied up, or held with a gun pointed at her head. She can't even handle a gun, so she has to be an NPC--any PC would have the Guns skill in that setting.
Wash is Zoe's dependent NPC. "But wait!" I hear. "He went off-ship with Mal in War Stories!" Uh-huh. Goes off to do something, gets kidnapped, has to be rescued by PC. That's, like, the definition of a dependent NPC.
Jayne looks like he could be a standard NPC, the one added to give more firepower to the party. But over the series it's obvious he's the PC of the newest player, the one who just wants to kill things and hates roleplaying. That's why the GM is inflicting big challenges such as a hero-worshipping town and million-credit reward offers on him, to force the player to roleplay instead of just rolling to-hit dice.
The most experienced player has Book as his PC. Clearly there's a 10 to 20 page backstory write-up for him, but nobody but the GM has seen it because it's all a bunch of Secrets. This guy must have a job and/or family because he keeps missing some of the sessions.
So where does Inara fit? She's not part of the main adventures, she keeps pulling the group away from its regular routine and putting them into new situations--a visit to Ariel, upper-class dueling, beleaguered whorehouses. Must be an NPC--clearly she's just a plot hooker.