Okay, I don’t know if anyone has posted this before, but assuming that Hurt has something to do with 10..
When Clara went down into the timestream, she saw all the doctors apart from 10, which could mean that Hurt is a figure related to 10. Clara said that she saw all 11 faces, but 10 wasn’t seen, suggesting that Hurt is 10.
In The Fires Of Pompeii, Evelina says “Even the word ‘doctor’ is false. Your real name is hidden. It burns in the stars, in the Cascade of Medusa herself.” – this clearly has some sort of relation to the Day Of The Doctor as it suggests that the Doctor has a real name that didn’t really surface within the 2008 series.
In The Name Of The Doctor, the Doctor says that the name ‘Doctor’ is a promise, and if Hurt was the one that broke the promise, this concludes the quote “the word ‘doctor’ is false”.
The oath and promise of a doctor in real life is to protect people and to look after them.. assuming that Hurt was the one who fought in the Time War, he broke the promise of a doctor. The only way for the Doctor to end the Time War would be his power to destroy all the daleks, and in doing so, destroying his own kind too. This is how he broke the promise.
Although, if Hurt is something to do with 10, then the theory of him being the incarnation between 8 + 9 and the one who fought in the time war wouldn’t work.
I thought that Hurt could be a guilty conscience of 10. (Leading back to the timestream thing) Hurt was the one who broke the promise. At this moment in time, we don’t know what the promise is, but it’s something that he carries a lot guilt for.
I’m probably far from correct though, haha.
