Doctor Who: 8 Characters Maisie Williams Might Be Playing

As production on the new series of Doctor Who continues in Cardiff, the BBC have been keeping things close to their chest in regards to what the Twelfth Doctor will be facing when he returns to our screens for his second string of adventures later this year. No news is good news, of course, but that still doesn't mean that even the slightest filming update is enough to send the show's fandom into an unprecedented speculative frenzy (don't judge, their lives have been unforgivably Who-less since Christmas Day, OK!?). Just imagine, then, the speculative chaos that has ensued as a result of yesterday's announcement that Game of Thrones star Maisie Williams will be guest starring in Series 9 (but what isn't she doing?!) as an unnamed character who is set to challenge the Doctor like nobody has ever challenged him before. A meaty statement indeed, especially since the Doctor is always meeting friends and foes who serve to push him to his emotional limits. So who - or what - will Maisie Williams be playing, and what about her will ensure that the Doctor is "out of his depth"? She'll "give him exactly the right sort of hell," according to Steven Moffat, but it looks like fans will just have to theorise about her identity until she arrives on our screens in the autumn. It's lucky, then, that theorising is something that Doctor Who fans can do very well. Without much further ado, here are 8 characters that Maisie Williams might (but probably won't be) playing in Series 9, from the relatively plausible to the downright ridiculous. But isn't the 'downright ridiculous' what Doctor Who is all about...?