Well my immediate thoughts that Missy is a female incarnation of the Master. Missy is a contraction of Mistress – ‘boyfriend’ is a rather twisted and lovely flip on the relationship the Doctor and the Master have had over the years.

Then I thought who else in Doctor Who history has been called Mistress – perhaps its a rather cross Romana?

THE RANI!!!!!!!!!!!!!

Not “Missy”. “Miss C.” as in Miss Clara. She’s one of the timestream split Claras. One who never met up with one of the Doctors and went batty. Why she’s collecting dead robotmen and making them think they’re in Heaven? Idunno.

I think she is just a glorified stalker.

its river song, thats my theroy.

@lolcats121
theory*

@lolcats121
theory*

I just know that I already don’t like her.

@Freddy Jones I don’t like her either, she seems incredibly crazy.

@lolcats121 I have a feeling we might not be seeming River again. And in any case River had no regenerations left, she died in the library as Alex Kingston’s version and there was no regeneration between little girl in America and Mels (Amy’s friend)

I don’t think there is any way that “Missy” is River. I also don’t believe that she is Clara. She was utterly unlikable in my opinion, but intriguing nevertheless…that has the feel of a master-y type villain. I’ll cast my lot with those who say she’s the “Mistress.”

My immediate thought was the Master.

Doubt she’s The Master. Could be an escaped criminal from Galifray?
I agree that ‘Missy’ is probably short for Mistress. A Timelady called ‘The Mistress’ would be interesting? If not very original.

My guess? She’s a new villian/reluctant heroine who is forced to help the doctor out near the end of the series. But up intil then, she is trapped in ‘The Nethersphere’ tasked as being the gatekeeper, unable to ever leave.

Side stepping slightly…
The Doctor is darker in this series. I would love for him to get more so through the episodes, until clara can no longer travel with him.
Realising he has lost her because of his actions, he somehow seperates his darker side, which creates a being called ‘The Valeyard’.

I think that she might be Clara Oswald because, she said, “did you fall, or did my BOYFRIEND push you, he can be so cross at times.” and earlier in the episode they were talking about how the Doctor was not Clara’s boyfriend and stuff like that, but once we find out more, we could figure out that she is some one totally new. Those are my thoughts. Also, I was surprised how many sound effects they used like when Clara got hit with the newspaper.

Could Missy not have been bluffing about the boyfriend thing?

@The 13th Doctor
Oooh, I like the sound of that.

Is she just collecting all the peoples deaths the doctor is responsible for?

perhaps…. I mean if she collected all those who were about to die she could amass an army… perhaps turn them into cybermen?????? Or even worse…..what if she saved DAVROS!!! because we never actually saw him die, we saw him scream and then we cut away into the tardis, in the “into the dalek” episode she saves people at the moment of their death like you said, ooooo I quite like where this could go…. think of the possibilities…..

@MelodicHarmony

The Doctor expressed a wish to correct mistakes. The TARDIS can correct a mistake the moment it happens or even the moment before. The TARDIS cares about the Doctor and wants to protect his psyche. The TARDIS can create or visit any environment.

Missy is in no way threatening or menacing to the people she saves. She them like guests… Or rescued strays.

Conclusion: Missy is the TARDIS.

The more I dwell on this theory, the more sense it makes. We’ve already been given several clues…

I doubt that she is Davros because he is all ugly looking and she is, well… A girl. I also doubt that she is the TARDIS because how could she be in “paradise” and still be with the Doctor? Different time zones? Maybe. But very doubt full. I think that she might be like a River Song. Mysterious, part or maybe even a full time lord, pops in and out don’t know much about her. But I don’t think that she is River Song, not to cause any confusion or anything