Doctor Who Series 8: 10 Reasons The Valeyard Is The Perfect Villain

6. The Master And The Valeyard Have Had Dealings

If the writers decide to bring back the Master anyway, they can still incorporate the Valeyard into a Master storyline. In The Trial of a Time Lord, the Master is the one who reveals the Valeyard's identity and explains how he is "an amalgamation of the darker side of the Doctor's nature". The Master also states that he wants the Valeyard out of the way because he doesn't want to deal with a rival. From this, it's fairly evident that the Master crossed paths with the Valeyard sometime before the Doctor did, and it would certainly be interesting to watch their interactions. Would they have been allies in some dastardly scheme? Even if they started that way, the Master's attitude in Trial indicates that he and the Valeyard had a falling-out. Considering how complex the Doctor and the Master's relationship has been over the years, the Valeyard-Master dynamic would probably have even more layers, and exploring this would make for some very interesting episodes.