Does Doctor Who's recent Timeless Child reveal clear up a lingering mystery from the David Tennant era? It's been over a decade since the final voyage of the Tenth Doctor in "The End of Time" but for many fans, those scars are still raw. The emotional climax of Tennant's TARDIS tenure saw The Doctor team up with John Simm's Master, as the duo prevented the Time Lords from escaping the sealed Time War and endangering 21st century Earth. The Doctor succeeded without succumbing to the "he will knock 4 times" warning but couldn't outrun fate, and ultimately sacrificed his present incarnation to save Wilfred Mott. The Doctor then embarked on a farewell tour of past companions.
While the David Tennant era neatly rounded off Russell T. Davies' time as Doctor Who's showrunner, and mostly answered all of the questions raised, there was one remaining speck of ambiguity that came in "The End of Time" itself. When the Time Lords arrive to confront The Doctor, they are joined by a woman, played by Claire Bloom, who resisted Rassilon's plan and is now being shamed. This same mysterious figure was seen warning Wilfred in the build-up to his adventure with The Doctor, and she shared a lingering look with David Tennant's hero that suggested a connection between the two. Davies later revealed that he cast Bloom with the intention she would play The Doctor's mother. Since this isn't explicit on-screen, however, the Time Lady could be Susan, The Doctor's daughter, Romana or some other family member.
The recent events of Doctor Who's season 12 finale, "The Timeless Children," put this mystery character in an entirely new context. Fans now know that The Doctor comes from another realm, rather than Gallifrey, so the woman from "The End of Time" definitely isn't the mother of Doctor Who's long-standing lead. Instead, the Timeless Child reveal offers another potential identity for the Time Lady - Tecteun. After The Doctor arrived in our world, Tecteun was the one who took her back to Gallifrey and scientifically engineered her biology to create the Time Lord race. Tecteun was an adoptive parent to The Doctor, was a high-ranking member of the Time Lord High Council, and could regenerate, all of which fits with the character the Tenth Doctor sees in "The End of Time."
On the other hand, the Doctor clearly has no memory of Tecteun after being mind-wiped by The Division in the pre-Hartnell period. There's definitely a spark of recognition on David Tennant's face when he sees this woman in his final episode, and this moment perhaps rules out her and Tecteun being one and the same. That is unless the Tenth Doctor's recognition was subconscious, and the reason he didn't reveal her identity to Wilfred was simply because he couldn't remember. Nevertheless, "The Timeless Children" throws out Russell T. Davies' preferred idea and the woman is now most likely to be an adoptive parent The Doctor grew up with after working for The Division.
Many Doctor Who fans likely thought this remaining Tennant mystery would never be revisited, but whether by accident or design, the Timeless Child arc forces viewers to consider it once more. Similarly, Chris Chibnall's huge canon expansion also explains the oft-discussed Morbius Doctors plot hole - an old Tom Baker episode that suggested other Doctors came before William Hartnell. However, season 12 creates inconsistencies faster than it solves them, such as Ruth's TARDIS being a police box and Clara not seeing the older Doctors when she entered Eleven's time stream. Fortunately, the mysterious Time Lady in "The End of Time" benefits from the Timeless Child, rather than being contradicted by it, since a definitive answer was never provided at the time.
Doctor Who returns with "Revolution of the Daleks" this holiday season on BBC and BBC America.