How many regenerations has the Master used so far?

Question

In the Doctor Who universe, the Master, like the Doctor, is a Time Lord with regeneration capabilities. I know he's been played by several different actors, ranging from Roger Delgado in Old Who to Derek Jacobi in New Who and most recently

Michelle Gomez as Missy

in series 8-9. We have also seen him regenerate on screen at least once (Jacobi -> Simm) and probably more times. But what about regenerations before the first shown in the show, or in between?

In-universe, do we know how many regenerations he has used throughout his life? And therefore how many he has remaining before he finally dies for good the showrunners come up with a way to keep him as a feature of the show (you can't keep a good Who villain down!)

Apologies for the masculine gender. It was partly to avoid spoilers for those who haven't seen Missy yet, and partly because "he/she" sounds clumsy and he has been male almost every time.

Answer 1

All of them, and then some

The Fourth Doctor episode "The Deadly Assassin" features the Master at the end of his regeneration cycle (emphasis mine):

Spandrell: It seems clear how it happened. The Master tried to trap the Doctor in the APC net by overloading the neuron fields. Then he collapsed and died, leaving Chancellor Goth still connected into the circuit.

Borusa: Natural causes?

Spandrell: Yes, sir. His body was extremely emaciated. He had come to the end of his regeneration cycle.

^{Doctor Who Season 14 Episode 3: "The Deadly Assassin"}

He got better, of course, and circumvented the limit by hijacking someone else's body. In "The Five Doctors", the High Council of Gallifrey offered the Master a brand new regeneration cycle, but it's not clear whether or not they delivered on that promise:

Master: What makes you think I want your forgiveness?

Castellan: We can offer you an alternative to your renegade existence.

Borusa: Regeneration. A complete new life cycle.

Master: What must I do?

Borusa: Rescue the Doctor.

^{Doctor Who "The Five Doctors" (1983)}

And, of course, he's been explicitly brought back to life at least twice, with an unknown number of regenerations earned each resurrection:

1. By the Time Lords to fight in the Time War:

   Master: The Time Lords only resurrected me because they knew I'd be the perfect warrior for a Time War.

   ^{Doctor Who Series 3 Episode 12: "The Sound of Drums"}

2. By the nutcases who brought him back in "The End of Time":

   Governor: Mrs Saxon. Let me introduce myself. I'm your new Governor. I'm afraid the previous Governor met with something of an accident, which took quite some time to arrange. Miss Trefusis, if you will prepare. You kept your silence well, Mrs Saxon. Your trial was held in secret, with no jury, so no one knows who Harold Saxon was, where he came from, why you killed him. Make her kneel. There are those of us who never lost faith. And in his wisdom, Harold Saxon prepared for this moment. He knew that he might die and he made us ready. Tonight, Mrs. Saxon, he returns.

   Master [OC]: [maniacal laugh]

   (Miss Trefusis holds out the Master's signet ring. Lucy gasps. Meanwhile, Wilf is looking out at the kitchen window at the storm while the Woman in White briefly appears on the TV screen in the other room.)

   Governor: As it was written in the Secret Books of Saxon, these are the Potions of Life.

   ^{Doctor Who "The End of Time Part 1"}

How many he has left at this point is really anyone's guess; considering how infrequently we see him, every change of actor could have an untold number of intermediate regenerations.

Known regenerations

All told, we know he's used at least 14:

• The original 12, ending with Pratt/Beevers
• Jacobi to Simm

• Simm to Gomez (off-screen)

Of the other actors to portray the Master, it's never 100% clear whether he regenerated into that new body, or simply aged into it:

• William Hughes played the young Master in the flashback in "The Sound of Drums" and "The End of Time"; that was probably his first body
• Roger Delgado played the Master during the Third Doctor's era. We don't know if the Master regenerated into the Delgado body, or if William Hughes grew up into Roger Delgado
• Peter Pratt and Geoffrey Beevers both played the Master at the end of his regeneration cycle; these are implied to be the same body. Once again, we don't know if there were any intermediate regenerations
• Anthony Ainley played the role for the last eight years of Classic Who, but he wasn't a regeneration; his was a body the Master stole
• Likewise with Eric Roberts, from the Movie

Answer 2

The reason he stayed alive all that time is because he didn't: he actually died a few times. I don't think he even regenerated all that much; instead he was resurrected a few times.

Don't believe well in the Doctor Who movie in which we see the 8th Doctor for the first time. At the beginning the Doctor is talking about how the Master has been executed for his crimes and he has been given the remains later; those remains possess a human and another Master is born. Another example is at the beginning of The End Of Time Part 1: we see a dark ritual in which Harold Saxon (a.k.a the Master) is resurrected. So actually the Master didn't regenerate all that often.

Answer 3

At least three full cycles that we know of. From Hughes to Pratt/Beevers was one and Ainley to Tipple was two. I believe the Man with the Rosetta, the Tzun Body, the Rathbone body, and Tipple are all actual incarnations as since we know he was promised a new cycle by the high council and knowing him he got it before going to the death zone. When the Tipple Master was killed the death worm took his essence and began hopping bodies starting with Bruce, who i'll count as an actual incarnation since he became trapped in the Eye of Harmony and is in a new cannon audio adventure as the Master, and ending with a second Beevers body given another cycle making Macqueen the first in cycle number three. As we don't know how many incarnations are between Macqueen and the Asian child we can assume Simms was the last in the third and first in the Fourth after being resurrected and granted a fourth cycle. Still have no clue on Sasha's Master, he could be a pre-Asian Child incarnation or a pre-Delgado incarnation we don't know.