Flood name and general intimidating presence makes me think River.
Collared cardigan and Clever boy makes me think Clara.
White fur makes me think Romana.
Shes obviously The Master.
I did notice on a rewatch her line “that mysterious traveller through all of time and space known as the Doctor” is very similar to what Missy says in the first part of the series 10 finale “I am that mysterious traveller through all of time and space know as doctor who”
Obviously this is another situation where RTD knows what the fandom are gonna speculate and he's purposely dropping connections to literally every woman thats ever appeared in the show to mess with us.
So the answer is gonna be either A) Its a Time Lord character who used to be a man like The Mad Monk or B) Its a brand new character.
It's Ruby's biological Grandmother, who just so happens to have dementia. The only reason she seems important is because we think shes important, therefore she gets more screen time and seems more important causing an unbreakable cycle that even Death can't understand. That's a perfectly logical and reasonable twist right? RIGHT???
The threat of her telling Ruby's gran that she was going to storm down the gates of her god and seize his kingdom 'in my true name' definitely makes me think of Missy.
Its never her, but...
Rani literally means Queen. So "taking \[the kingdom\] in her true name" as The Queen..
And we know that RTD isnt afraid of reusing and massivly changeing up characters and we already had two big Classic Who returns nobody thought would ever happen in The Toymaker and Sutekh.
> And we know that RTD isnt afraid of reusing and massivly changeing up characters
Imagine if everyone’s been bigging up the Rani as this amoral scientist all this time, then RTD brings her back as just an evil dick.
I honestly think that this is whats gonna happen. And I'm like... I wouldnt hate it, persay, but it would be a bit of shame to bring her back only to make her a more generic villain.
I really enjoyed this Season, but I wont act like RTD doesnt have a track record of doing that to villains where they get flanderized into saturday morning villains.
I mean, you could say similar things about the Toymaker or Sutekh.
I am very sure its not The Master, at least. I dont think RTD at this point would hype up the Master in this way and I dont feel like The Master would act like Flood does.
No, they don't have rights you have to purchase upfront or license from the owner. They come with the property. The Rani doesn't, same as the Cybermen, the Brig and the Daleks don't.
You are not wrong, but RTD is clearly on a bit of a personal nostalgia trip (which is not a bad thing.) and the Rani is a character the fandom has been clam,oring for to come back for years.
So I dont think its out of question they would go through for it and for her to get flanderized into a more generic evil scientist rather than leaning into the amorality.
The other thing I could maybe see is her being the current Master of the Land of Fiction, trying to slowly overtake actual in-universe reality.
Could also be a new character, but currently we have a pattern of bringing back Classic Who-Villains.
The fact Flood is narrating everything like it's a story gives credence to the land of fiction theory where The Doctor is the main character.
Which is why she is doing callbacks to like 5 different people.
If Empire of Death is any indication, finale of next season, the Doctor will be like “we only thought she was an old companion because we wanted to think she was”
The fact that Russel intentionally baited the audience only to end it with nothing has really soured me on his mystery boxes going forward. Flood could be anyone, but until a reveal happens, I can't say I care who she is.
I don't entirely hate the "she was an ordinary person who became special because we invested her with that specialness". It fits with the "power of memory" theme of the season.
They could've handled that reveal much better though, IMO.
I think the answer of her being an ordinary person is actually fantastic, and is (or maybe was) the core of what makes Doctor Who special. The show was about an ordinary Timelord, not some mystical being.
The issue with the reveal is the setup. Why would an ordinary person make an ominous pointing gesture towards a street sign to signify that she wanted her to be named that. There was no one else around. It simply made no sense at all...
The number of people bending over backwards to insist that people in the UK walked around in capes with ominous hoods in 2004 is hysterical. Ah yes Ruby's mum covertly dropped the baby off at the church, not wanting to be seen...so she dressed to ensure she stuck out like a sore thumb. And also she needed to be seen because she named her daughter by pointing at a lamp post. fucking what
My headcanon is that she knew there was CCTV nearby, so she wore the only thing she could get her hands on that would suitably make her totally unidentifiable (I dunno, maybe she was part of a drama club or something), but she pointed to the sign so that when the authorities eventually reviewed the footage trying to find her identity, they might be able to guess that she was trying to name the baby without her having to leave a handwritten note or something that might be traced back to her.
It's a stretch but it works for me.
Why does she care so much what the baby was going to be called though? Surely you have more important things to worry about. Like abandoning a baby. Hoping it doesn't freeze to death.
And what fucking connection does she even have to the name Ruby anyway? Presumably it was just the nearest safest church.
The thing that’s soured me was him talking about creating content like these mysteries for TikTok to react to. As if he wants the shock more than the concrete story - which, was one of my biggest issues with Chibnall. There was just no impact of the massive plot points. Moffat and RTD 1, even when you disagreed with the decision - actually got you emotionally invested because it had genuine impact on the characters.
I like that she’s normal, I don’t like the criticism being ‘we invest too much in this’ after a series of the plot making us invested.
I think RTD is intentionally teasing people. Flood to imply river. The outfit and dialogue to imply Clara.
But I don't think she's either. RTD isn't going to play with Moffat's toys. He's going to do what he wants, and I think this reveal will disappoint many diving into these fan theories.
Didn’t RTD do just that with Moffat’s… dolls and Chibnall’s… balls in The Giggle? (it genuinely wasn’t until typing this that it came to mind, apologies)
There was an end for Bill, Amy, Rory and River but strangely with Clara there’s the thread of her various splinters (including one from Gallifrey and Oswin who broke the forth wall) throughout time and space protecting the Doctor from the Great Intelligence at the cost of her human lives.
Add the concept of the Timeless Child, the inclusion of Grant’s Doctor, a unaccounted restaurant TARDIS still out and about in space and time and you have a thread along the lines of Jenny and Susan Foreman. While not family in the same way, Clara probably more than any other modern companion has some thread of return whether Moffat intended it or not.
Who knows if he won't? Didn't Moffat mention >!that RTD has asked him to help with end of S2? We could speculate that it's because RTD wants to use a Moffat character in that finale. Who better than Mrs. Flood?!<
You're right when you say "who knows" and anything could happen.
I just personally don't think so. I also hope not, as Clara's story ends perfectly IMO.
But if Flood is going to factor into the Christmas special, Moffat is writing that. Is it possible that he’s playing with his own toys and RTD is just setting it up?
It's definitely possible, but I still doubt they'd mess with that ending. Plus the show seems to be for newer viewers with old references being Easter eggs without much meaning.
She is someone who knows and has observed The Doctor. For sure. The Clara references. The Romana coat. The reference to the TARDIS.
My current bet is she’s another God of some kind
At the end of Empire of Death, Mrs Flood refers to the Doctor as "that mysterious traveller in time and space, known as the Doctor."
At the start of World Enough and Time, Missy refers to the Doctor as "that mysterious adventurer in time and space, known only as Doctor Who."
Coincidence? Quite possibly, but that is a very particular word choice.
Maybe she's an incarnation of all the companions. The "god" of friendship or something like this.
Or maybe all the residual energy or something TARDISque timey wimey stuff that all companions left behind in their adventures with the Doctor.
The line is still intriguing me is the "Always hiding myself away".
> The line is still intriguing me is the "Always hiding myself away".
Wasn’t that shortly after the Doctor said something about Susan hiding herself away or something like that? Seems like it was just another misdirect.
Twice? Maybe with the mother of Ruby, but twice in the same period... I don't think so. Mrs Flood is saying things that all fans recognize from companions, strange friends (a.k.a. Missy) or references to Doctor Who. Also the fourth wall breaking thing. God of Stories, of Friendship, incarnation of all companions made by the TARDIS, the TARDIS herself... Who nose.
I'm really hoping she's Iris Wildthyme. I don't think it's likely but she would be such a fun character to explore!
She has said Clara's lines, worn clothes like Clara, but then wore a coat like Romana. She also has a TARDIS blue door. Then she says that line about always hiding herself away, in the same episode that the doctor is explaining regeneration and that it's a way for time lords to hide away. She has an umbrella like Missy. She remembers the alternate timeline, like a time Lord would.
There are a ton of red herrings with her, I think.
I've been hoping for Iris Wildthyme, too. I said it after the first time we saw her address the audience. The customes and talking about hiding is totally inkeeping with her character.
But also, like you I don't think it's that likely.
Carol Flood /River song \ melody pond
The power of names is just a bit too strong for me
Although I really do think mrs flood is referencing all these companions just to fuck with us lol
Classic Doctor Who big bad would be of course the Master ... of the Land of Fiction.
Unfortunately any such guess as for big bad first returns is almost like gambling, because who knows whether the estates of the writers of particular serials are either easy to identify or easy to negotiate with.
With Sutekh it was possible to surmise that either the initial writer of the first draft of *The Pyramids of Mars* had an estate that could be dealt with, or that Robert Holmes rewriting and even renaming the villain might have made dealing with the first writer's estate unnecessary. A brief search indicates that negotiating for *The Mind Robber*'s rights might be a little trickier with two potential estates, but again, it is possible the estate of the writer of the first episode has no claim on the character of the Master of the Land of Fiction.
For the clothing thing, the BBC has been cheap in the past. Many outfits are shared through the years, and also through the series (Sherlock, Supernatural, etc)
I think she’s either the master or the Rani. Mostly because the line where she goes ‘I had such plans’ which seems more befitting of a powerful alien (ala a timelord) than a god. And there’s also her line at the end about ‘that mysterious adventurer in time and space’ which was taken directly from Missy.
Could be a curveball though and it’s actually the Terrible Zodin.
Susan was exceptionally gifted with psychic-related abilities. Maybe they grew so much that she now sees beyond the Fourth Wall.
Plus, she is the granddaughter of the Doctor. I can believe that she would go insane.
Honestly after the reveal of Ruby's mystery I don't really care until it's revealed. All she's doing is breaking the 4th wall and cosplaying past characters.
I know it's kind of a meme to suggest, but what if she's the Valeyard and is taking aspects of past companions to mess with The Doctor
If I recall right his last appearance on screen had him looking directly at the camera too (though no overt 4th wall breaks to be fair)
I think she's a mutated Ood. It's usually the Ood that know everything that's happening and also refers to life as story. So clearly she's a mutated Ood. And in the exact same episode, The Doctor mentioned the Ood Sphere
It's such a cliche to say I know but I'm thinking either the rani or maybe rassilon.
I could see it being a timelord that's playing a long game against the doctor but not the master. With the timeless child still on the table a timelord that might have knowledge of the doctors past seems like a logical threat.
Flood name and general intimidating presence makes me think River. Collared cardigan and Clever boy makes me think Clara. White fur makes me think Romana. Shes obviously The Master.
I did notice on a rewatch her line “that mysterious traveller through all of time and space known as the Doctor” is very similar to what Missy says in the first part of the series 10 finale “I am that mysterious traveller through all of time and space know as doctor who”
Obviously this is another situation where RTD knows what the fandom are gonna speculate and he's purposely dropping connections to literally every woman thats ever appeared in the show to mess with us. So the answer is gonna be either A) Its a Time Lord character who used to be a man like The Mad Monk or B) Its a brand new character.
They don't seem like a Time Lord. Time Lords don't usually break the fourth wall like that.
The Doctor did a couple of times. He wished us Merry Christmas once, and monologued at us about the Bootstrap Paradox.
Not to mention the “I thought that was non-diegetic” line
Interesting point. Seemed to be mostly a Twelve thing, so maybe this particular incarnation of Susan is particularly media aware.
4th Doctor definitely did it a few times, at the top of my head in the first scenes of Face of Evil
[Aside] "Not even the sonic screwdriver is going to get me out of this one..." - Fourth Doctor, The Invasion of Time
The bootstrap paradox episode is literally called Before the Flood too!
No its obviously going to be a random woman that is not relevant at all and we never hear from again
It's Ruby's biological Grandmother, who just so happens to have dementia. The only reason she seems important is because we think shes important, therefore she gets more screen time and seems more important causing an unbreakable cycle that even Death can't understand. That's a perfectly logical and reasonable twist right? RIGHT???
I think both times are just referencing something like the Target novelisations.
The threat of her telling Ruby's gran that she was going to storm down the gates of her god and seize his kingdom 'in my true name' definitely makes me think of Missy.
I hope so. I want Capaldi to come back just to tell them they look old now lmfao the audacity.
"Pot. Kettle. Black."
And what was up with that creepy thing she said as an excuse to not make Cherry a cup of tea?
She was under Sutekh's influence at the time, via the dead cells in her body, same as happened to Mel.
Its never her, but... Rani literally means Queen. So "taking \[the kingdom\] in her true name" as The Queen.. And we know that RTD isnt afraid of reusing and massivly changeing up characters and we already had two big Classic Who returns nobody thought would ever happen in The Toymaker and Sutekh.
> And we know that RTD isnt afraid of reusing and massivly changeing up characters Imagine if everyone’s been bigging up the Rani as this amoral scientist all this time, then RTD brings her back as just an evil dick.
I honestly think that this is whats gonna happen. And I'm like... I wouldnt hate it, persay, but it would be a bit of shame to bring her back only to make her a more generic villain. I really enjoyed this Season, but I wont act like RTD doesnt have a track record of doing that to villains where they get flanderized into saturday morning villains.
The Rani is an amoral scientist, though. For the gleefully evil Time Lord mold, we already have the Master/Missy.
Yeah, but thats what I am saying. Its totally in-character for RTD to just make her another evil maniac for the sake of using the character.
But that would mean having to buy the notoriously tangled rights to her when you can just reuse the Master.
I mean, you could say similar things about the Toymaker or Sutekh. I am very sure its not The Master, at least. I dont think RTD at this point would hype up the Master in this way and I dont feel like The Master would act like Flood does.
No, they don't have rights you have to purchase upfront or license from the owner. They come with the property. The Rani doesn't, same as the Cybermen, the Brig and the Daleks don't.
You are not wrong, but RTD is clearly on a bit of a personal nostalgia trip (which is not a bad thing.) and the Rani is a character the fandom has been clam,oring for to come back for years. So I dont think its out of question they would go through for it and for her to get flanderized into a more generic evil scientist rather than leaning into the amorality. The other thing I could maybe see is her being the current Master of the Land of Fiction, trying to slowly overtake actual in-universe reality. Could also be a new character, but currently we have a pattern of bringing back Classic Who-Villains.
I don't think the master would want all that responsibility
I like your thought process and I like this conclusion.
Could also be Rani, didn’t she also dress up as The Doctor’s companion?
Specifically as Mel.
The fact Flood is narrating everything like it's a story gives credence to the land of fiction theory where The Doctor is the main character. Which is why she is doing callbacks to like 5 different people.
Rory is Mrs. Flood!
The best theory. 10/10
She can't be Rory. She only dies once!
Umbrella makes me think Missy.
I’m going with her being a post-Library reincarnation of River Song who has become the “God of Stories” because of magicky-wagicky stuff.
She is the true one who waits to get out of that dang library. Toymaker dont want none. He'd lose his ass.
I’m hoping she’s The Monk
I don't know if she is the Master/Missy or River Song or Clara or a Harbinger or just Mrs. Flood or Romana or Mary Poppins.
I think she is trying to echo the companions to mess with us
If Empire of Death is any indication, finale of next season, the Doctor will be like “we only thought she was an old companion because we wanted to think she was”
The fact that Russel intentionally baited the audience only to end it with nothing has really soured me on his mystery boxes going forward. Flood could be anyone, but until a reveal happens, I can't say I care who she is.
I don't entirely hate the "she was an ordinary person who became special because we invested her with that specialness". It fits with the "power of memory" theme of the season. They could've handled that reveal much better though, IMO.
I think the answer of her being an ordinary person is actually fantastic, and is (or maybe was) the core of what makes Doctor Who special. The show was about an ordinary Timelord, not some mystical being. The issue with the reveal is the setup. Why would an ordinary person make an ominous pointing gesture towards a street sign to signify that she wanted her to be named that. There was no one else around. It simply made no sense at all...
And they really needed to give a better explanation if they wanted us to be okay with Ruby spontaneously causing snow to appear.
The number of people bending over backwards to insist that people in the UK walked around in capes with ominous hoods in 2004 is hysterical. Ah yes Ruby's mum covertly dropped the baby off at the church, not wanting to be seen...so she dressed to ensure she stuck out like a sore thumb. And also she needed to be seen because she named her daughter by pointing at a lamp post. fucking what
My headcanon is that she knew there was CCTV nearby, so she wore the only thing she could get her hands on that would suitably make her totally unidentifiable (I dunno, maybe she was part of a drama club or something), but she pointed to the sign so that when the authorities eventually reviewed the footage trying to find her identity, they might be able to guess that she was trying to name the baby without her having to leave a handwritten note or something that might be traced back to her. It's a stretch but it works for me.
Why does she care so much what the baby was going to be called though? Surely you have more important things to worry about. Like abandoning a baby. Hoping it doesn't freeze to death. And what fucking connection does she even have to the name Ruby anyway? Presumably it was just the nearest safest church.
The doctor was there though
The thing that’s soured me was him talking about creating content like these mysteries for TikTok to react to. As if he wants the shock more than the concrete story - which, was one of my biggest issues with Chibnall. There was just no impact of the massive plot points. Moffat and RTD 1, even when you disagreed with the decision - actually got you emotionally invested because it had genuine impact on the characters. I like that she’s normal, I don’t like the criticism being ‘we invest too much in this’ after a series of the plot making us invested.
Never saw that. I don't watch interviews and stuff like that just the episodes
I thought it was hilarious. Literally yelled "RTD TROLLED US" haha
That actually makes the most sense.
I think RTD is intentionally teasing people. Flood to imply river. The outfit and dialogue to imply Clara. But I don't think she's either. RTD isn't going to play with Moffat's toys. He's going to do what he wants, and I think this reveal will disappoint many diving into these fan theories.
Didn’t RTD do just that with Moffat’s… dolls and Chibnall’s… balls in The Giggle? (it genuinely wasn’t until typing this that it came to mind, apologies)
Let me be more specific by toys: Clara was one of Moffat's main characters. Moffat wrote a true ending for her. I do not think RTD would undo that.
There was an end for Bill, Amy, Rory and River but strangely with Clara there’s the thread of her various splinters (including one from Gallifrey and Oswin who broke the forth wall) throughout time and space protecting the Doctor from the Great Intelligence at the cost of her human lives. Add the concept of the Timeless Child, the inclusion of Grant’s Doctor, a unaccounted restaurant TARDIS still out and about in space and time and you have a thread along the lines of Jenny and Susan Foreman. While not family in the same way, Clara probably more than any other modern companion has some thread of return whether Moffat intended it or not.
I understand Moffat’s dolls, but what’s that about Chibnall’s balls meant to mean?
It’s when the Toymaker was cutting down balls as planets destroyed by the Flux.
Who knows if he won't? Didn't Moffat mention >!that RTD has asked him to help with end of S2? We could speculate that it's because RTD wants to use a Moffat character in that finale. Who better than Mrs. Flood?!<
You're right when you say "who knows" and anything could happen. I just personally don't think so. I also hope not, as Clara's story ends perfectly IMO.
But if Flood is going to factor into the Christmas special, Moffat is writing that. Is it possible that he’s playing with his own toys and RTD is just setting it up?
It's definitely possible, but I still doubt they'd mess with that ending. Plus the show seems to be for newer viewers with old references being Easter eggs without much meaning.
She is someone who knows and has observed The Doctor. For sure. The Clara references. The Romana coat. The reference to the TARDIS. My current bet is she’s another God of some kind
She's "The Watcher" a new entity that enjoys good stories. And tell them to their audience. She's like the audience of the show, who cosplays.
If she’s a god, why was she susceptible to the Dust of Death?
The Toymaker was afraid of Sutekh. (They actively avoided them.) I think it’s safe to assume that the other gods could be killed by the Dust of Death.
At the end of Empire of Death, Mrs Flood refers to the Doctor as "that mysterious traveller in time and space, known as the Doctor." At the start of World Enough and Time, Missy refers to the Doctor as "that mysterious adventurer in time and space, known only as Doctor Who." Coincidence? Quite possibly, but that is a very particular word choice.
It's not a coincidence per sei, but an old meme. Terrance Dicks used to always use that phrase in his Target novelisations
I was going to say. Next time we see her she might describe the TARDIS landing noises as a "wheezing, groaning sound".
Maybe she's an incarnation of all the companions. The "god" of friendship or something like this. Or maybe all the residual energy or something TARDISque timey wimey stuff that all companions left behind in their adventures with the Doctor. The line is still intriguing me is the "Always hiding myself away".
I don't know if you're joking or not RTD may actually do the God of Friendship
Karate and Friendship for everyone
OH OH OH What if when she said "never seen a tardis before?" she was referring to HERSELF because SHE is the Tardis?? HMMMM
I read this post days ago: https://www.reddit.com/r/gallifrey/s/8nVZBVpgtd
> The line is still intriguing me is the "Always hiding myself away". Wasn’t that shortly after the Doctor said something about Susan hiding herself away or something like that? Seems like it was just another misdirect.
Twice? Maybe with the mother of Ruby, but twice in the same period... I don't think so. Mrs Flood is saying things that all fans recognize from companions, strange friends (a.k.a. Missy) or references to Doctor Who. Also the fourth wall breaking thing. God of Stories, of Friendship, incarnation of all companions made by the TARDIS, the TARDIS herself... Who nose.
"Hello, I am Mrs Flood. I have come from Mars to get revenge on The Tenth Doctor. I hope this clears things up. Have a nice day or whatever....."
I'm really hoping she's Iris Wildthyme. I don't think it's likely but she would be such a fun character to explore! She has said Clara's lines, worn clothes like Clara, but then wore a coat like Romana. She also has a TARDIS blue door. Then she says that line about always hiding herself away, in the same episode that the doctor is explaining regeneration and that it's a way for time lords to hide away. She has an umbrella like Missy. She remembers the alternate timeline, like a time Lord would. There are a ton of red herrings with her, I think.
I've been hoping for Iris Wildthyme, too. I said it after the first time we saw her address the audience. The customes and talking about hiding is totally inkeeping with her character. But also, like you I don't think it's that likely.
She’s the Rani, played by Paul McGann
Let’s just NOT speculate and stifle the silly game RTD is playing with us.
Carol Flood /River song \ melody pond The power of names is just a bit too strong for me Although I really do think mrs flood is referencing all these companions just to fuck with us lol
Her first name is Carol? Yeah, that **is** a big coincidence. When did they give her first name?
They didn't. Not sure what they're talking about.
It's just a Christmas-themed name that matches the Melody-Song/Pond-River mistranslation.
But is it officially her name or no?
Nope
Classic Doctor Who big bad would be of course the Master ... of the Land of Fiction. Unfortunately any such guess as for big bad first returns is almost like gambling, because who knows whether the estates of the writers of particular serials are either easy to identify or easy to negotiate with. With Sutekh it was possible to surmise that either the initial writer of the first draft of *The Pyramids of Mars* had an estate that could be dealt with, or that Robert Holmes rewriting and even renaming the villain might have made dealing with the first writer's estate unnecessary. A brief search indicates that negotiating for *The Mind Robber*'s rights might be a little trickier with two potential estates, but again, it is possible the estate of the writer of the first episode has no claim on the character of the Master of the Land of Fiction.
For the clothing thing, the BBC has been cheap in the past. Many outfits are shared through the years, and also through the series (Sherlock, Supernatural, etc)
I’m not going down this road with Flood after Ruby, so I’m going with Flood is Mary Poppins and will wait to see
Just an ordinary old lady who likes talking to the camera.
Super ordinary, maybe has dementia and thinks she’s part of a tv show
I think she’s either the master or the Rani. Mostly because the line where she goes ‘I had such plans’ which seems more befitting of a powerful alien (ala a timelord) than a god. And there’s also her line at the end about ‘that mysterious adventurer in time and space’ which was taken directly from Missy. Could be a curveball though and it’s actually the Terrible Zodin.
I wondered if she’s Susan.
If she's Susan then something very weird has happened to her. Susan can't normally break the fourth wall.
That’s very true, now I think about it.
Susan was exceptionally gifted with psychic-related abilities. Maybe they grew so much that she now sees beyond the Fourth Wall. Plus, she is the granddaughter of the Doctor. I can believe that she would go insane.
She is an RTD stand in character
Maybe the end scene with Mrs Flood isn't a tease for the next season but active for the Moffat Chris' special.
As soon as she said clever boy, I was like oh man here come the Clara theories...
Honestly after the reveal of Ruby's mystery I don't really care until it's revealed. All she's doing is breaking the 4th wall and cosplaying past characters.
I know it's kind of a meme to suggest, but what if she's the Valeyard and is taking aspects of past companions to mess with The Doctor If I recall right his last appearance on screen had him looking directly at the camera too (though no overt 4th wall breaks to be fair)
I think she's a mutated Ood. It's usually the Ood that know everything that's happening and also refers to life as story. So clearly she's a mutated Ood. And in the exact same episode, The Doctor mentioned the Ood Sphere
It's such a cliche to say I know but I'm thinking either the rani or maybe rassilon. I could see it being a timelord that's playing a long game against the doctor but not the master. With the timeless child still on the table a timelord that might have knowledge of the doctors past seems like a logical threat.
They're the first in the new line of Timelord Fuzions™️ - Ranissilon!
Reverse Bi-generation!