10 Doctor Who Characters You Completely Changed Your Mind About

2. River Song

Oh, River Song. What would Doctor Who be without you? That's a serious question, too, since the show has effectively been defined by her for most of Steven Moffat's era. Originally introduced as an enigmatic professor who seemingly knew everything there was to know about the Doctor (hell, she even knew his name, for God's sake - pretty disconcerting since he'd never seen her in his life!), River sacrificed herself to save him at the end of the Series 4 two-parter, Silence in the Library and Forest of the Dead, and the majority of fans assumed that they'd never see her again. How wrong they were. River came back with an almighty vengeance at the start of Matt Smith's tenure and things escalated very quickly when she was revealed as Amy and Rory's daughter and kidnapped at birth to be raised into a psychopathic killing machine who would one day shoot the Doctor dead in the guise of an impossible astronaut. Seriously. Love or hate River (and there's seemingly no in between), you can't deny that she got dangerously close to becoming too much of a good thing. In fact, fans just assume that she's somehow behind pretty much everything that happens these days, and any new character or ally is assumed to be a regenerated version of her until proven otherwise. Because she has Time Lord tendencies, too, just to make her even more special. The Doctor's wife... the Doctor's killer... the Doctor's equal. If this continues, she'll end up being the Doctor himself one of these days. Stranger things have happened.