Every hero needs a proper arch enemy to face off against. It's fair to say that The Master is one of the best villains on TV. Doctor Who is one of Britain's longest-running series which makes the Master one of Britain's longest-running villains.

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Doctor Who fans love to create fan theories and The Master is such a complicated and mysterious character that there's plenty to talk about in regards to theories about the Time Lord. We're taking a look at 10 crazy fan theories from over the years that actually turned out to be true!

HE CAN RETURN FROM GALLIFREY

Gallifrey

During the final showdown between the Doctor and the Master, events were set into motion that could not be reversed. This was a big television event that saw the final stand of the 10th Doctor, with David Tennant retiring from the role.

However, before this famous regeneration scene, the Master sacrificed himself, saving the Doctor, with the Master getting sent into the depths of the hellish, war-torn Gallifrey. Fans theorized that this wasn't the true end of the Doctor and that he could somehow return. They turned out to be right!

HE NEVER DIED

Every time that the Master has a death, fans theorize that he didn't die at all. It happened in the early days of Doctor Who where it seemed like the Master was killed for good on a weekly basis. It happened during the break between the original series and the reboot too, which we'll talk about later.

Even recently, when Missy took over, fans would theorize that she could still return despite facing certain doom. Even now that Missy and The Master appear to be dead, fans are still speculating on ways that they could be revived. Like every time before this, it's probably true.

YOU ARE NOT ALONE

During the days of the 10th Doctor, he was warned by the Face of Boe that he was not alone. This kind of mystery had fans obsessed immediately as they were not sure what this could mean. Some started to speculate that it was referring to another Time Lord.

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The Doctor had assumed that all the Time Lords were dead and that he was the last one. But the theories flooded in that the Master was set to return. When we were introduced to Doctor Yana it was revealed that Yana stood for You Are Not Alone. He turned out to be the Master confirming the theories.

THE MASTER CAN CHANGE GENDER

For some time, fans have speculated whether regeneration can affect gender. It's been discussed a few times and we've seemingly seen evidence of this. However, we never knew whether this kind of change would be made to a major character.

It seems funny now, considering the Doctor is now female, but many started suggesting that the next regeneration of the Master could indeed be female. This would then set up the idea that the Doctor could be female as well. This all turned out to be true.

MISSY IS THE MASTER

Around the same time that people started to discuss the possibility of a gender change, fans started guessing what the real identity of Missy was. It seems obvious looking back, especially based on the name, but there was a genuine mystery surrounding the reveal of this character.

When it finally came to tell us who this quirky and stern character was, fans were ready to be proven wrong. Yet to their surprise, Missy really was the Master and served as the nemesis of the 12th Doctor until her apparent death.

TRAPPED SOUL

There were multiple theories suggesting that the Master had actually trapped his soul in order to survive. We'd previously seen that Time Lords could use pocket watches in order to remove anything alien about them. They forget their life and register as human.

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This had happened to the Doctor and he lived a completely different life for some time. However, this story was just a setup to bring back the Master. This is how he returned in the form of Doctor Yana. The scientist had a pocket watch that he eventually opened, restoring the villain.

CHILDHOOD FRIENDS

There was always an interesting dynamic between this hero and villain. There was a level of friendship there and almost admiration and respect, not seen between the Doctor and his other enemies. The level of hatred for the Daleks for instance just didn't carry over to The Master.

Many people made the assumption that the two were brothers. While it's never been confirmed if they have the same mother, they do not have the same father. But, the two were in fact brothers of sorts, growing up together, going to school alongside one another and becoming best friends in their childhood.

THE DRUMS

For a while, the four knocks plot line dominated Doctor Who. The Doctor was said to die once he had heard the four knocks. People started speculating that these drums were, in fact, the heartbeat of a Time Lord. That actually turned out to be true.

The drums had been in the Master's head for some time and fans started to connect the drums and the four knocks with one another. While the Master was in part responsible for the death of the Doctor, confirming most suspicions, it wasn't actually the final four knocks that the prophecy spoke of.

LOVERS

Many fans have created their own fan fiction about the Master and the Doctor. There's been some momentum for the notion that the Master and the Doctor had been lovers in a past life and still hold some kind of affection for one another.

Once the Master turned into Missy this was pretty much confirmed. Missy was flirtatious and the two even kiss at one point. This helped a lot of fan theories gain even more traction and we look back at the times the Master also seemed to flirt and perhaps even find the Doctor attractive.

THE MASTER IS NO LONGER A TIME LORD

The fate of the Master has been discussed a lot. After the first death of the John Simm master, many thought that he would be brought back but as less than human. When he then appeared he was a creature of sorts, eating raw meat and acting like an animal.

The Master has been less than human in the past, appearing as some sort of carcass of a man during the early days of the show. He has even turned into other things including a snake during the film. The Master appeared to be a Time Lord again recently but this could be reversed once more, as it has been in the past.

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