10 Biggest Doctor Who Theories About Susan Twist's Mysterious Character

Summary Susan Twist's mysterious appearances could be key to uncovering Ruby Sunday's origin story in Doctor Who season 14.

The inclusion of Triad Technology and a potential new Master theory adds depth to the ongoing intergalactic mystery.

Could Susan Twist be a member of the all-powerful Pantheon? Her presence in every episode suggests an intriguing tie to the overarching plot.

Susan Twist's mysterious Doctor Who character has sparked many theories about who she is and what her significance is to the storyline. The iconic British science fiction series is again being penned by Russell T Davies, who is known for inserting seemingly random details that become significant later on. The first few episodes of the first season to be streamed on Disney+ have contained many Doctor Who Easter eggs that could also be clues as to what will happen later in the season, especially in relation to discovering the truth about new companion Ruby Sunday (Millie Gibson)'s origins.

The Doctor Who cast for the newest season has included an actress who plays bit roles in every episode. Susan Twist has appeared in four different Doctor Who roles so far, suggesting that there is something more to to inclusion of this actress than preferring to have the same person play a small part in each story. This theory has been bolstered by the inclusion of a random song about a twist at the end of "The Devil's Chord," which could be a reference to the actress' name meant to foreshadow her importance to the overall storyline.

Every Susan Twist Appearance in Doctor Who So Far Role Played Episode Mrs. Merridew (Isaac Newton's assistant) "Wild Blue Yonder" Woman at concert "Church on Ruby Road" Comms Officer Gina (dying crew member) "Space Babies" Tea Lady "The Devil's Chord" Ambulance "Boom"

Susan Twist's mysterious appearances in every episode could be a red herring meant to distract the audience from noticing major clues elsewhere in the episodes. However, it's more likely that her appearances have something to do with the central mystery surrounding Ruby's origins. Here are ten of the biggest theories about who Susan Twist might really be.

10 Doctor Who's Susan Twist Is Ruby's Birth Mother

She Could Be Keeping Tabs on Ruby For Reasons of Her Own

Close

Doctor Who has already dropped several hints that Ruby Sunday's search for her birth parents may not be as straightforward as it seems. Ruby seems to have mysterious energy that draws the Doctor (Ncuti Gatwa) and the TARDIS to places where other abandoned children are in need of help, and the Maestro was terrified of what they learned about the circumstances of Ruby's birth and subsequent abandonment at the church. The Doctor also scanned Ruby's DNA in the TARDIS, suggesting that her origin is not human.

Thus, one logical theory about Susan Twist is that she is Ruby's birth mother. It is not yet known why Ruby was abandoned at the church as a baby, but Susan Twist could be following her, either to keep her out of trouble or to keep an eye on what she's doing and what she knows about her origin. This theory explains why Susan Twist keeps showing up wherever Ruby goes; her character could be disguising herself as random people so that she can watch Ruby without being detected.

This theory could also explain why Ruby seems to be drawn to certain places. The Doctor noticed she was connected to abandoned babies, but if Susan Twist's character is her birth mother, she could be the force attracting Ruby and the Doctor to places where babies need help. Ruby has not noticed any shifts in her energy around Susan Twist's mysterious character yet, but that doesn't necessarily disprove the theory because the character could be able to block Ruby's awareness of their connection.

9 Doctor Who's Susan Twist Could Be Associated With Triad Technology

This Fictional Tech Company Name Was Spotted On The Side of a Bus During the Christmas Special

"The Church on Ruby Road" featured an unusual advertisement on the side of a bus for Triad Technology, a company that supposedly offers IT solutions. There were no mentions of the company during the episode other than the random shot of the advertisement, but since Russell T Davies often disguises significant clues as random occurrences, the company name could be significant. Thus, Susan Twist could be someone associated with that company. If so, it is possible she is a villain who has not revealed her true identity.

Triad Technology was first mentioned during "The Giggle," when Melanie Bush told Donna that UNIT used Triad tech to create a sub-frame Donna was trying to access.

If this is the case, there are several possibilities. Susan Twist's character could be an evil tech mogul who is after the Doctor and Ruby for unknown reasons, perhaps having to do with futuristic technology that the Doctor needs to stop from destroying the universe. Ruby's birth also could have been engineered using technology offered by this company, and Susan Twist's character could be monitoring Ruby so that she doesn't learn the truth about her origins.

The Doctor Who season 14 trailer features David Tennant's Doctor appearing as a hologram, which is likely related to Triad Technology. Thus, another possibility is that Susan Twist's character is a hologram or other form of AI programmed to appear wherever the Doctor and Ruby do. This would fit in with the theory that Triad Technology was involved in Ruby's birth and wants to keep its secrets hidden. The AI played by Susan Twist could be programmed to distract Ruby or otherwise stop her from learning the truth about Triad's involvement in her birth.

8 Doctor Who's Susan Twist Could Be a New Regeneration of the Master

The Master Could Have Turned Into Missy Again

Russell T. Davies has announced he is retiring the Master from Doctor Who, which would seem to make it unlikely that Susan Twist is a new version of the character. However, when the Master is in female form, they go by the name "Missy," short for Mistress. Thus, Davies could have technically been telling the truth while keeping it under wraps that he does plan to bring back the Master in a different form. If this is the case, Missy could be disguising herself as unremarkable people while she is waiting to make her next move.

The Master/Missy has always enjoyed disguises, dating back to their early appearances during the Jon Pertwee years. Thus, it would be completely in character for Missy to take various forms and insert herself into the Doctor and Ruby's adventures. If this were the case, Missy would most likely be keeping tabs on the Doctor while setting things up for some elaborate plan to gain power and destroy the universe that she will eventually put into place.

All The Actors Who Have Played The Master/Missy Actor Years Played Roger Delgado 1971 - 1973 Peter Pratt 1976 Geoffrey Beevers 1981 Anthony Ainley 1981 - 1986 Eric Roberts 1996 Derk Jacobi 2007 John Simm 2007 - 2010; 2017 Michelle Gomez 2014-2017 Sacha Dhawan 2020

If Missy is behind the Susan Twist appearances, that would also offer an alternate explanation for why Ruby seems drawn to certain places. It could be Missy's TARDIS that is actually attracting the Doctor and Ruby, disguised sufficiently that the Doctor is unaware of it. Thus, the Doctor has mistakenly labeled Ruby as the cause of the TARDIS' attraction to certain situations.

There is one flaw in this theory, however. The Doctor ought to be able to sense when another Time Lord is around despite his belief that he is the only one left. This doesn't necessarily invalidate this theory because Missy is particularly adept at hiding her true identity, including any Time Lord energy that the Doctor would ordinarily pick up on.

7 Susan Twist Is a New Version of the Rani

The Renegade Time Lord Has Yet to Appear in Modern Doctor Who

The Rani is a classic Doctor Who villain who was introduced in the Colin Baker Episode "Mark of e Rani." Like the Master, she is a renegade Time Lord who left Gallifrey after breaking many of its laws. The Rani is amoral, caring only about scientific research and exhibiting no concern for who she hurts in the process. She has not appeared in the reboot of Doctor Who up until this point. However, the Doctor mentioned her during "Space Babies" when talking about the type of names Time Lords tend to be given.

There have been rumors circulating about the Rani's return since RTD took over as showrunner. The Doctor mentioning her name could be foreshadowing that she is finally coming back to Doctor Who. If this is the case, Susan Twist would be an ideal person to play her. The Rani would enjoy experimenting with using science and technology to mess with the Doctor. She might also have experimented with human DNA to create Ruby in the first place.

6 Susan Twist Is Another Time Traveller

She Could be a Time Lord But Doesn't Have to Be

Susan Twist's continual appearances are somewhat reminiscent of Doctor Who's River Song, who knew the Doctor without him knowing her because their timelines weren't synced. River turned out to be Amy Pond's daughter, who was conceived while traveling in the TARDIS and therefore inherited Time Lord characteristics such as being able to time travel and regenerate. Similarly, Susan Twist's character could be another Time Lord or time traveler who knows the Doctor and Ruby despite their lack of awareness about her identity.

This theory explains why Susan Twist has appeared in every episode of Doctor Who during season 14. However, if she is a time traveler, it is unclear what her purpose is in seeking out the Doctor and Ruby. She may have become stranded in time and latched onto the TARDIS in the hopes of getting back to where she is supposed to be. Alternatively, she could be a villain who is hoping to disrupt the space-time continuum by continually interacting with the Doctor and Ruby.

5 Susan Twist Is the Mysterious Figure Who Picked Up the Master's Gold Tooth

This Theory Assumes She Is Not the Master or Rani

"The Giggle" set up a mystery that has not yet been addressed involving a woman whose face was not shown. The Toymaster bragged to the Doctor (David Tennant) that he had defeated the Master and turned him into nothing but a gold tooth. After the Doctor's bi-generation and the Toymaker's defeat, however, a hand was seen picking up that gold tooth. The most logical explanation is that Missy picked up her previous regeneration's tooth, but an alternate theory involves Susan Twist.

If Susan Twist is not playing the Master or Rani, then it could be a brilliant twist for her to be the person in possession of the Master's tooth. This would introduce a new mystery about who she is and why she wanted the Master's tooth. Additionally, it is possible that she gained the ability to time travel or regenerate from touching the Master's tooth. This could lead in fascinating directions, depending upon why she is appearing everywhere the Doctor and Ruby do.

4 Susan Twist Is a Member of the Pantheon

These All-Powerful Villains Terrify the Doctor

Close

The Pantheon are Doctor Who season 14's primary villains, who have been described as godlike, immortal creatures who have so much power that the Doctor cannot fight them and must run away. Susan Twist's character has appeared in every episode that involves a member of the Pantheon, with the exception of "The Giggle." Susan Twist's character seems to show up wherever Pantheon members do, suggesting that she is associated with the omnipotent creatures.

If Susan Twist is a member of the Pantheon, it doesn't necessarily mean she's evil, although so far the Pantheon has caused nothing but trouble. She could be a rogue member who is trying to stop the others from wreaking havoc or is trying to protect Ruby and the Doctor from the other members of the Pantheon. The Doctor does not have the intense fear of her than he does of other members of the Pantheon, which seems to contradict this theory, but if she were a force of good instead of evil, that could explain the discrepancy.

3 Susan Twist's Character Could Be Doctor Who's The One Who Waits

This Mysterious Moniker Has Been Given to a Powerful Alien Who Might Have Been Involved With Ruby's Abandonment

The One Who Waits is presumably an extremely powerful member of the Pantheon. The Toymaker warned the Doctor about him, saying that he was the only being the Toymaker could not defeat, and the Maestro backed off Ruby while trying to steal her song once they learned that The One Who Waits might have been present at the church when Ruby was abandoned. This mysterious being has been referred to with male pronouns, but that doesn't necessarily mean anything.

All-powerful beings could be genderless or encompass all genders, so Susan Twist could still be the One Who Waits.. If so, that would tie in to previous theories about her character keeping tabs on Ruby because of Ruby's desire to know her origins. Susan Twist could also be playing the One Who Waits' disguise, which could then lead to a reveal of the powerful being's true form.

2 Susan Twist Is Doctor Who's Ruby Sunday From Another Timeline

Like Mrs. Flood, She Could Be an Older or Alternate Version of Ruby

It's theoretically possible that Susan Twist is an older version of Ruby. However, the Doctor has emphasized that there would be serious consequences if Ruby were to meet another version of herself, which is why he can't take her to the church to witness her birth. This presents a problem for the theory that Ruby and Susan Twist's characters are the same person, as the two have interacted without creating a paradox or other problem. However, while Susan Twist's character can't be an older version of Ruby, she could be an older version of an alternate timeline's Ruby.

Rose Tyler created a similar paradox during "Father's Day" by stopping her father from dying when she was a baby.

Under the multiverse theory of time travel, Ruby could have created a split between this universe and another one when she stepped on the butterfly or when the Doctor revived it. In this case, there could be another Ruby in another universe who is still a butterfly hybrid. There could also be other Rubys from other universes because of other small moments in Ruby's life that have changed things. Susan Twist's character could be an older version of one of those Rubys, thus avoiding the time paradox when meeting this Ruby.

1 Susan Twist Could Be Doctor Who's Susan, The Doctor's Granddaughter

The Doctor and Ruby's Discussion of His Granddaughter Might Not Have Been Random

Close

Doctor Who's Susan Foreman (Carole Ann Ford) was the Doctor's first companion and was said to be his granddaughter. The Time Lords were supposedly all destroyed in the Time War except for the Doctor, but that's been proven to be false by the Master's return. The Doctor's recent comments that Susan likely is dead suggest that the opposite is true and that she will return eventually.

Related Doctor Who: What Happened To Susan, The Doctor's Granddaughter The First Doctor left his granddaughter, Susan Foreman, on Earth, but Doctor Who media has provided several updates on her status since then.

If Susan is still alive, Susan Twist could be playing her. She could be following the Doctor and Ruby because she wants to reconnect with her grandfather. Alternatively, Susan could have lost her memories during the Time War and feel a pull toward the Doctor without understanding the reason, which could explain her disguising herself as various people rather than telling him who she is. This would be an interesting Doctor Who twist that tied the newest season to its 1963 debut.

Doctor Who season 14 streams on Disney+