Which theory about the Hybrid’s identity is most likely to be correct? [closed]

Question

I want to find out which theory about the identity of the Hybrid (as mentioned in the recent Doctor Who episode “Heaven Sent”) is the most probable to be true. It's not like there are not dozens of them online but I want to know the opinion of someone who has the knowledge to explain every aspect of it.

So, I have to begin with the "Valeyard" theory: This one is obvious, so not bulletproof, the Veil followed the Doctor in a castle with a yard. This could be a good reference as the Valeyard (pronounced vel-yard) being the next future threat to the Doctor, or even himself (a threat to the Time Lords), as stated in the Classic Who.

Next, the Cartmel Masterplan. To begin with a little history:

...Omega and Rassilon were the founding fathers of Gallifrey. They towered above the Time Lords who followed. They were demigods. [Dialogue in Silver Nemesis was] a subtle attempt to say that there was a third presence there in the shadowy days of Gallifrey's creation. In other words, the Doctor was also there. So he's more than a Time Lord. He's one of these half-glimpsed demigods.

The Hybrid could be The Other, a past(or future regeneration of the Doctor). We know that Steven Moffat is a great classic-whovian, so he might want to revive an old story. Therefore, how could he introduce this?

In the end, the origin theory. At the end of the episode, the Doctor says:

The Doctor: Go to the city. Find somebody important. Tell them, I'm back. Tell them, I know what they did, and I'm on my way. And if they ask you who I am, tell them, I came the long way round.

You can probably still hear me... so just between ourselves... you've got the prophecy wrong. The Hybrid is not half Dalek. Nothing is half Dalek. The Daleks would never allow that. The Hybrid destined to conquer Gallifrey and stand in its ruins... is me.

And we find out that the Hybrid is a combination of the greatest two warrior races. That could be the Time Lords and the humans(we reached the end of the Universe, didn't we?). This could lead also to the fact that he will fight with other Time Lords in the following episode. Other way of looking at this sentence is that Lady Me/Asildr, the latest immortal character that appeared in the show, is going to destroy Gallifrey. She already appeared in three episodes and she seems that has more to go.

Answer 1

The prophecy is vague, it states that a person of two warrior races is destined to conquer Gallifrey and stand in its ruins.

Lets say the Doctor is the hybrid. The prophecy never stated that the person had to have a biological parent of each race. The Doctor is a member of Earth, he is the President of Earth in emergency global situations and he works for UNIT. The Timelords are fully aware the Doctor deems Earth as his own, under his protection, due to his love for mankind.

He is also a Timelord, this makes up two warrior races. Earth qualifies as one of the mighty warrior races since they had a huge empire in the year 200,000 (Series 1) and stayed alive until the end of the Universe (Utopia).

You can also say that he is half-human, as seen in the Doctor Who movie starring the Eigth Doctor:

I'm half-human, on my mother's side.

Despite that statement in the audio books it has been cleared up that that was a trick by the Doctor using the Chameleon arch to fool the Master.

Now, lets say Me/Ashildr is the hybrid. Ashildr was Viking, a mighty race of Humans and she is also powered by Mire technology (The Girl Who Died). She does appear in series finale and she is a hybrid. The Doctor does say "Me", however he never refers to Ashildr as me, and in the script Ashildr is referred to Ashildr, only Ashildr refers herself as "Me".

Answer 2

On the one hand, the Doctor says "the Hybrid is me", so let's assume he's correct. His statement didn't surprise me at all. I suspected that there would be more to, ahem, Me, when she first said that was her name.

However, I'd also like to muddle the waters a bit.
Do you remember what the Eight Doctor said in the movie? Right.

I'm half-human, on my mother's side.

So there you have it. The Doctor is a hybrid. Has been, in canon, for nearly 20 years.