Despite seemingly being vanquished, two powerful Doctor Who foes may be set for a frightening family reunion as Russell T Davies teases the Fifteenth Doctor's (Ncuti Gatwa) greatest fight in season 15's two-part finale. Across the latest season of the long-running sci-fi series, the Time Lord has been tasked with bringing Belinda Chandra (Varada Sethu) back home to present-day Earth, though something is preventing the TARDIS from landing. Meanwhile, the pair have been stalked by the enigmatic Mrs. Flood (Anita Dobson) across time and space, while former companion Ruby Sunday (Millie Gibson) and UNIT have contended with misinformation campaigns.

Across their travels in Doctor Who season 15, the Doctor and Belinda have had to contend with new foes that continue to blur the lines between the real and the fantastical. From the God Lux Imperator (Alan Cumming) in 1950s' Miami, to an angered Barber (Ariyon Bakare) exacting revenge on the deities who wronged him in 2019 Lagos, more all-powerful beings are manifesting in the Whoniverse. Per Davies' tease when promoting the simultaneous release of season finale "The Reality War", something worse is yet to come for the Time Lord, as three certain figures stand in his way.

Doctor Who's "Unholy Trinity" Teases The Toymaker & Maestro Returning

The Pantheon Is A Family Affair

As part of a wider press release for "The Reality War", the Doctor Who showrunner stated that "The Unholy Trinity rule supreme and the Underverse is rising" when setting up the status of the Whoniverse going into the finale. At the time of writing, no three beings encountered in either the 60th-anniversary, season 14, or season 15 have held such a title. However, a connection between two preexisting major antagonists may hint towards their identities.

Within the events of the 60th-anniversary special, the Toymaker (Neil Patrick Harris) was unleashed on the universe thanks to a gambit made by the Fourteenth Doctor (David Tennant), and with him his "Legions". One such creature was the Maestro (Jinkx Monsoon), the God of Music, who erases all music from the Earth in 1960s' England and states that they are a child of the Toymaker. Though their family may expand to the rest of Doctor Who's mysterious Pantheon, the title of the trio of villains could hint at a much more personal link.

Neither the Toymaker or Maestro were explicitly killed in their adventures, merely banished or imprisoned.

The title of the "Unholy Trinity" is obviously inspired by the concept of the Trinity in Christian doctrine, which states that God exists as three divine persons, the Father, the Son, and the Holy Spirit that altogether define what God is. By title alone, the Toymaker would fit the position of The Father, while Maestro would fit The Son, leaving the Holy Spirit yet to be represented. However, while one member may be missing still, what they represent when united is also up for discussion.

Another Clue Was Dropped During Doctor Who's 60th Anniversary

The Toymaker's Realm May Offer A Glimpse Of What's To Come

However, Davies' tease may have also hinted at what this Unholy Trinity may invoke when brought together, as the "Underverse" may have already been alluded to. As the Fourteenth Doctor ventured into the Toymaker's shop with Donna Noble (Catherine Tate), he explained just how he first met the Toymaker. As he recollects his past encounter, the Time Lord states that the Toymaker's realm resided in "A hollow beneath the Under-Universe," before describing the dangers of the Toymaker's domain.

With this description, it can be theorized that if the Unholy Trinity does feature the Toymaker and Maestro, the Underverse and Under-Universe may be connected. From the Doctor bringing up the concept of the Under-Universe when discussing how the Toymaker's realm doesn't follow the rules and physics of the known universe, it can be assumed that the Under-Universe similarly isn't bound by those rules. In the hands of the wrong being with the right power, like the Toymaker, the Under-Universe could be similarly malleable to a powerful being.

Within his realm, the Toymaker could render the Doctor completely invisible on a whim, bring life to inanimate objects, control beings, and manifest his realm where he pleases.

As such, if the "Under-Universe" and "Underverse" are the same, and the latter is rising, it could mean that the laws that dictate our own universe could be broken, leaving it to rewritten by whatever being controls it. For beings like the Gods of the Pantheon of Discord, who are bound by rules, making the universe more malleable will allow them to live up to their name by sowing disorder. The universe may be thrown into chaos, but none of the Doctor's tricks would be able to stop them, making the season 15 finale have the highest stakes faced yet.

Who The Third Member Of Doctor Who's Holy Trinity Could Be

One Recurring Figure May Be The Final Piece Of The Puzzle

If the Toymaker and Maestro are indeed part of a larger entity, that could mean that the final aspect currently exists in the Whoniverse. Certain established of the Pantheon have been vanquished on-screen, such as Lux and Sutekh (Gabriel Woolf), ruling them out of a reappearance. Other named entities, such as the Mara and the Trickster (Paul Marc Davies), have also presumably been vanquished in past adventures before the current era.

One such figure who seems like an obvious contender for the "Spirit" of the Unholy Trinity is Mrs. Flood herself. Though she stood on the sidelines during season 14, season 15 has shown that she can manifest anywhere across time and space. This would align well with the Holy Ghost's role, as it is stated to lack a physical form to limit it, explaining why Mrs. Flood can manifest wherever she wishes at any time.

Furthermore, Mrs. Flood has already made explicit references to the Christian faith through her exchange with Cherry Sunday (Angela Wynter) in "The Legend of Ruby Sunday", as she declares that she will tear down all God created. By making her state that she is in opposition to God itself, it could have acted as an early piece of foreshadowing for her role within the Unholy Trilogy. As such, season 14 may have already revealed her true allegiances.

With three episodes to go, audiences will not have to wait long for the truth of the Unholy Trinity to be revealed. Throughout its new era, Doctor Who has broken down the boundaries of universes to create some of the most powerful foes the Doctor has faced. And with something preventing him from returning to May 2025, it is likely that whatever waits, be it familiar foes or something far worse, will shatter his reality forever.