In the series 7 finale The Name of the Doctor, the Great Intelligence ran down a list of titles that were associated with the Doctor, and one of these was "Valeyard". This was not the first time the Doctor had been associated with the Valeyard; we first learned of this mysterious character in 1986, and there has been a whole lot of discussion about him lately. Some people are wondering if John Hurt's character in the 50th anniversary special is really the Valeyard and not some in-between Doctor after all, while others are guessing if the Valeyard will soon reappear on the show now that the Doctor is set to enter his twelfth regeneration at Christmas. But with all this in mind, we have to ask the question who is the Valeyard, and why is his name associated with the Doctor's? If they are two different people, why did the Great Intelligence refer to them as if they were the same person? And what does any of this have to do with the Doctor's twelfth regeneration? To start off, "Valeyard" was the title of the Time Lord prosecutor in The Trial of a Time Lord, the season-long story arc from 1986 that saw the Doctor on trial for his transgressions against the Law of Non-Interference. The Valeyard was a stubborn, arrogant individual, and the Doctor took an instant dislike to him, using every opportunity that arose to insult him. Yet still, his constant insults masked a deeper concern. The Valeyard seemed bound and determined to bring down the Doctor, even going so far as to manipulate evidence to make the Doctor appear guilty--which the other Time Lords involved in the trial maintained was impossible; no one could enter the Matrix and rewrite the information it contained. The Master managed to disprove this statement by crashing the Doctor's trial in his usual flamboyant fashion. Why did the Master show up at the Doctor's trial? Much to the Doctor's surprise, it was to help prove his innocence. The Master held no great love for the Valeyard and didn't relish the idea of competition...even if it was in the form of his oldest friend. Yes, to the shock of all present, the Master revealed that the Valeyard was a future Doctor. Even so, he was more than just a future regeneration he was a physical manifestation of the Doctor's dark side, the Dream Lord made flesh. He had been "born" sometime in the Doctor's twelfth incarnation and had crossed his timeline to return to Gallifrey. His plan was to get the Time Lords to execute the Doctor for breaking the Law of Non-Interference and, in return for doing such a good job for the prosecution, be granted the Doctor's remaining regenerations. By seizing control of the Doctor's remaining lives, he undoubtedly wanted to reshape the events that have been so integral to the modern series, namely the Time War. The Doctor managed to prove his innocence and defeat the Valeyard, but his evil double found a way to survive. It is unknown if he played any part in the Time War. With the Eleventh Doctor about to regenerate and the Twelfth prepared to take center stage, fans everywhere are assuming the Valeyard can't be far behind. How he comes to be, how he manages to return to a pre-Time War Gallifrey, and what, if any, extra havoc he wreaks in the Doctor's life are sure to make for thrilling episodes for Peter Capaldi's tenure in the TARDIS.