While making the original McGann series, we carefully sidestepped using the Alex Macqueen Master. This was for a couple of reasons but mostly, because our series predated his introduction. Of course, we could have used him during our Time War movie, Children of Gallifrey, but with so much going on, we felt it would be a waste.
Which brings us to Requiem.
We approached Season 26C differently to the McGann stories. Rather than the plots being resolved at the end of each episode, we left them dangling. Not forgotten, but also, not referenced in the next story. All so we could produce: Requiem.
This story sees the War Doctor retire to his childhood barn and recollect his adventures in the supposed presence of the Master, filling in the blanks we missed out on throughout the rest of the series.
With appearances from both the Macqueen Master and the telepathic Ood, this story ends with the Doctor edging dangerously close to declaring "No More," as depicted in the fiftieth anniversary special: The Day of the Doctor.
This episode uses the following Non-Who sources:
Krapp's Last Tape
Crime and Punishment
Highlander: The Raven (Inferno)
The Oxford Murders