Ncuti Gatwa’s time on Doctor Who has come to an end. Though his tenure proved a lot shorter than most of his predecessors, Gatwa made every episode as the Fifteenth Doctor shine in ways that tugged at fans’ heartstrings. Of course, this also meant Gatwa had to make an epic, high-stakes exit as the Time Lord. To that end, the Doctor Who Season 2 finale, “The Reality War,” didn’t disappoint.
“The Reality War” did more than give Ncuti Gatwa his swan song, however. Apart from the Season 2 companion, Belinda Chandra (Varada Sethu), “The Reality War” also brought back many fan-favorite characters like Ruby Sunday, Kate Lethbridge-Stewart, Melanie “Mel” Bush, Rose Noble, and Poppy.
The Doctor Who Season 2 finale also brought back some old faces, like Jodie Whittaker’s Thirteenth Doctor and Billie Piper, seemingly as the Sixteenth Doctor. Though Russell T Davies did end Gatwa’s tenure as the Fifteenth Doctor on an explosively high note, it still left a lot of questions unanswered.
Why Did the Fifteenth Doctor Think About Rose Tyler When Regenerating?

One of the biggest surprise returns in “The Reality War” is Billie Piper, seemingly as the Sixteenth Doctor. Though the end credits simply state “Introducing Billie Piper,” this is the second time the Doctor regenerated into a face he has seen before. The first time was when his Twelfth incarnation took on the appearance of Lobus Caecilius, played by Peter Capaldi.
Originally, the Doctor explained that he took on Caecilius’ appearance as a means of reminding himself of why he saves people. He was, of course, referring to the fact that he almost didn’t save anyone from the Pompeii disaster in Series 4, and only did so on Donna’s insistence. Since the Fifteenth Doctor seemingly took on Rose Tyler’s appearance, it does beg the question of why he thought of Rose?
The last time the Doctor saw Rose was in the Series 4 finale “Journey’s End.” In the episode, his Tenth incarnation left Rose on her parallel Earth with his half-human clone. Since the Doctor has started valuing family by his Thirteenth incarnation and briefly gained a family with Belinda Chandra, did he once more think of his love for Rose? If Doctor Who is renewed for another season, the answer to this question will be interesting to explore. Even more so since The Moment also took on Rose’s appearance in the Doctor Who 50th Anniversary Special, “The Day of the Doctor.”
What Happened to the Fourteenth Doctor?

One loose end that’s not tied up by “The Reality War” is the fate of the Fourteenth Doctor. Although this incarnation of the Doctor played by David Tennant stayed on Earth to recover from all of his trauma with Donna Noble’s family, what he does after his recovery is still up in the air. The same goes for his duplicate TARDIS as well.
Could this be the reason the Fifteenth Doctor gained Rose Tyler’s face post-regeneration? Will the Sixteenth Doctor reunite the Fourteenth Doctor with Rose Tyler in her parallel reality? This might be a future story in the making.
How Did the Doctor Meet Susan, and Why Does She Call Him ‘Grandfather?’

One of the biggest reveals in “The Reality War” is the Time Lords not being able to have children. This does make sense given the immortal nature of the Time Lords, their regenerative ability, and the fact that they get their entire DNA template from the Timeless Child. This also puts Susan’s origins into question.
If the Doctor had no biological children (which contradicts the previous times he said he was a father), who exactly is Susan Foreman? Flashbacks have confirmed that Susan did originate on Gallifrey, but she was never explicitly confirmed to be a Time Lord. She was also never once seen regenerating. Is Susan the child of another Gallifreyan the Doctor adopted at one point? Would this be the reason Susan would call a Time Lord her grandfather? This, too, will need to be elaborated upon at some point.
What Is the Connection Between Omega and the Timeless Child?

Another mystery that’s left unsolved by “The Reality War” is Omega’s own connection to the Timeless Child. It was previously believed that Omega was the first Time Lord, until the Master learned Tecteun actually created the Time Lord race by gene-splicing the Timeless Child. The Rani certainly still believes he is the original Time Lord who invented Time Travel. It also seems as though the Rani is aware of the Master’s genocide of the Time Lords on Gallifrey since she escaped.
It doesn’t seem as though the Rani is aware that the Doctor is the Timeless Child. This also means it’s not known if Omega also became a Time Lord due to Tecteun’s experiments, or via other means. Does Omega even know that the Doctor is the Timeless Child, and therefore, the actual original Time Lord? The only thing that hasn’t changed about Omega is that he remains at the center of the Time Lord myth, but a lot remains unexplored as to how he truly gained that status in the first place.
Why Did Omega Choose a Corpse-Like Appearance in the Antimatter Universe?

Another thing that hasn’t changed about Omega is that he remains bound to the antimatter universe. Since this dimension became his permanent prison, he hasn’t been able to return to the positive matter universe in a new body without decaying. Another way he remained permanently bound to the antimatter universe was by constructing the world he knows purely out of his own will. This also caused him to lose his original body in the process.
It appears as though Omega willed a new body for himself in the antimatter universe, but it begs the question of why he chose a mummy-like appearance. After all, Omega believes himself to be a god – or, at least, believes he should be worshipped like one.
Since he was last seen wearing regal-looking armor, what made him exchange this look for a more corpse-like appearance? Was his will not strong enough to give himself a completely new body? Does this also say something about his ability to regenerate? Since he absorbed Archie Panjabi’s Rani, Omega will need a proper follow-up if Doctor Who gets renewed for a new season.
Did Belinda Chandra Forget Poppy While Travelling With the Doctor?

One thing that definitely changed by the Doctor Who Season 2 finale is the reason Belinda Chandra wanted to return home. Originally, it was because she had a job to go to in the morning. After the Doctor altered reality to save Poppy (his and Belinda’s daughter in “Wish World”) from erasure, this no longer appeared to be the case.
While the Doctor changing reality seems to provide the straightforward answer to the change in Belinda’s motivations, it still raises a lot of questions. For instance, during Belinda’s trip to the planet Missbelindachandra One, time was corrupted en route. The Doctor also felt this time disruption inside the TARDIS. Furthermore, the Rani had been manipulating time from the start, using the Doctor’s vindicator.
The other event that puts Belinda’s memories into question is the appearance of Poppy in the Season 2 episode, “The Story & the Engine.” Poppy originally appeared as “Captain Poppy” in the Season 1 episode “Space Babies.” But in “The Story & the Engine,” Poppy appeared to Belinda as a lost child on the streets of Lagos, Nigeria. Did Belinda see her future daughter or the daughter she had forgotten? Given the creation of alternate realities in Season 2, both could be true.
Is Poppy Still a Space Baby?

Continuing the mystery of Poppy is the fact that there now appears to be two different versions of her in existence. As mentioned, the original Poppy appeared as the infant captain of a starship in “Space Babies.” Since then, another version of Poppy appeared as the daughter of Belinda Chandra.
The question remains: did “Wish World” create a doppelgänger of Poppy based on the wishes of Conrad Clark? Did the Doctor actually wish this new version of Poppy into existence? Did the Rani herself create Poppy as a Space Baby and later repurposed her for the events of “Wish World”? As cute and adorable as Poppy is, she remains one of the Whoniverse’s biggest mysteries.
Why Are Mundy Flynn and Belinda Chandra Genetically Identical?

Perhaps the biggest unsolved mystery of Doctor Who Season 2 is the Mundy Flynn and Belinda Chandra connection. Originally appearing in Season 1’s “Boom,” Mundy was an Anglican soldier fighting a never-ending war on Kastarion 3. When the Fifteenth Doctor met Belinda in the Season 2 premiere, he immediately recognized her face as Mundy’s.
In “The Robot Revolution,” the Doctor reasoned that Mundy had to be Belinda’s descendant. The thing that puzzled him, however, was the fact Mundy and Belinda were genetically identical. Though the Doctor wanted to solve this mystery, he ultimately never did. At best, fans theorized another Oswin and Clara Oswald situation, with Belinda and Mundy being temporal duplicates of each other. This would have aligned with the events of Seasons 1 and 2.
The Doctor also felt something was binding him and Belinda together, but this bond was never truly explained. The only certainty surrounding Belinda and the Doctor was her being a part of the Rani’s plans for the Doctor from the start. Ruby also factored into those plans, given the Doctor’s own affinity for blonde women. After all was said and done, however, it was never explained why the Rani wanted Belinda as the Doctor’s companion. The Rani similarly never explained if Mundy also factored into those plans, or if she existed as a consequence of time being altered.
Why Didn’t Ruby Sunday Recognize Belinda Chandra as Mundy Flynn From ‘Boom?’

In addition to the Mundy Flynn mystery never being resolved, Ruby Sunday also never recognized Belinda. This is odd considering Ruby interacted quite a bit with Mundy in “Boom.” Though Ruby didn’t meet Belinda until “Wish World,” she still should have recognized her face when her full memories were restored.
Ruby did recognize Poppy from “Space Babies” and is the only one who remembered her when time was altered. In fact, she insisted that the Doctor find a way to save her. Ruby also recognized UNIT’s Scientific Advisor, Shirley Bingham, in the altered reality of “Wish World.” Furthermore, Ruby remembered experiencing an alternate version of 2025 in Season 1’s “73 Yards.” Given Ruby’s expansive memory across multiple timelines, it’s odd she wouldn’t remember Mundy Flynn.
Who’s ‘The Boss?’

The biggest unanswered question of “The Reality War” is the identity of “The Boss.” This mystery character was first mentioned by the Meep in the Doctor Who 60th Anniversary Special, “The Star Beast.” More specifically, the Meep said their “Boss” was interested in a being with two hearts. Similarly, the Toymaker mentioned encountering a being so terrifying, he didn’t bother engaging this entity in a game. Overall, the 60th anniversary specials hinted at the return or arrival of a powerful entity.
Between Seasons 1 and 2, fans speculated at who this “terrifying” entity would be. At first, it was assumed to be Sutekh, the God of Death. This made sense, as Sutekh is known in the Whoniverse to be a terrifying god. But Sutekh never confirmed he was the entity the Toymaker feared, nor the Meep’s “boss.”
After Mrs. Flood was revealed to be the Rani, fans began to speculate she would turn out to be this terrifying “boss.” This too made sense since the Rani sees the whole universe as one giant experiment. She would most definitely be interested in a being with two hearts, especially the Timeless Child. But again, this is never confirmed. As such, this terrifying “Boss” remains an unsolved mystery.
Why Did the Various Gods Have the Toymaker’s Giggle?

The recurring theme throughout Russell T Davies’ second Doctor Who era is the Pantheon of Gods. The Toymaker was the first confirmed god, who used “The Giggle” to manipulate reality. Other Gods that were introduced betweens Seasons 1 and 2 also laughed the same giggle. These included Maestro (the God of Music), Lux (the God of Light), and the infant God of Wishes.
Though it made sense for Maestro to do the Toymaker’s giggle as the latter’s child, it was never explained why the other gods had the same laugh. Initially, it was assumed all of these gods were foreshadowing the arrival of a more terrifying god, but this never materialized. Thus, the recurring giggle remains unexplained.
What Happened to the Pantheon of Gods After the Rani Was Defeated?

Following Tecteun’s near destruction of the universe in Doctor Who: Flux, the universe was left in a vulnerable state. Flux also established the existence of parallel realities with different laws of physics. Given this vulnerability, entities from beyond the universe like the Not-Things and the Toymaker started making their way into the universe to wreak havoc.
After the Rani destroyed one version of the universe in “The Reality War,” more realities began to emerge. What allowed the heroes to remember their original lives was Anita opening the door to the Time Hotel. After the Doctor used regeneration energy to make one final alteration to reality, it’s left unknown what became of the Pantheon of Gods.
Did the Doctor’s alteration of time finally patch the holes in reality left behind by the Flux event? Or did this leave the universe even more vulnerable? If renewed for a new season, Doctor Who will need to provide a definitive answer.
Who Picked Up The Master’s Gold Tooth?

The final mystery that’s left unresolved by “The Reality War’s” finale is who picked up the Toymaker’s gold tooth containing the Master. It was reasonable to think this was the Rani since she turned out to be the main villain of Season 2. The Rani has also teamed up with the Master before.
Ultimately, the Rani never confirms if she did pick up the Toymaker’s gold tooth, or is keeping the Master somewhere. If Doctor Who gets pick up for future seasons, either Russell T Davies or a future showrunner will have to follow up on that.