Warning: Spoilers ahead for Doctor Who season 15, episode 6, "The Interstellar Song Contest."end of Doctor Who season 14 proves that returning showrunner Russell T. Davies isn't against bringing classic villains back into the fold.

Gatwa entered the fray via the iconic bi-generation scene. Since then, Fourteen has been resting on Earth while Fifteen continues the Doctor's legendary adventures through time and space. Very few familiar faces can be found among his library of villains so far, but the groundwork has now been laid for further rematches.

5 Maestro

The God of Music's debut episode also teased their return

Gatwa's third episode as the face of Doctor Who, "The Devil's Chord," wasted no time in introducing a powerful enemy for the Fifteenth Doctor. Building on Davies' Toymaker retcon in 2023's "The Giggle," Neil Patrick Harris' Doctor Who character was brought into the fold retroactively. Although the Doctor and Ruby defeat Maestro (with a little help from The Beatles), the God's exit doesn't seem to be all that permanent.

It wouldn't make sense for Doctor Who to reveal the continued presence of Maestro's Harbinger unless the plan was for the God of Music to return someday.

Kit Rakusen's Henry Arbinger and his presence near the end of "The Devil's Chord" and its wild musical sequence tease Maestro's return. Bound by the rules of the Pantheon, a God's presence is always foreshadowed by a Harbinger, and Henry is Maestro's. Rakusen's character is the piano student at the start of the episode, and he looks the same at the end, despite the opening scene being set decades earlier. It wouldn't make sense for Doctor Who to reveal the continued presence of Maestro's Harbinger unless the plan was for the God of Music to return someday.

4 Roger ap Gwilliam

"73 Yards" introduced a fairly grounded villain

Played by Aneurin Barnard, Roger ap Gwilliam has only properly appeared in Doctor Who season 14, episode 4, "73 Yards," although he does also briefly factor into the story of "Empire of Death." Either way, he doesn't enter the Doctor Who universe as a viable threat until the 2040s, as proven by Ruby Sunday's alternate future in "73 Yards." He's the leader of a far-right political party that wins the UK general election. When the Albion Party wins, he becomes the UK Prime Minister, and looks set to enact all the troubling policies he's pushed during his campaign.

Roger ap Gwilliam's nickname, Mad Jack, is found in the fairy circle at the beginning of "73 Yards." While the episode never explains this, it suggests the character has some sort of supernatural connection.

Barnard's character's most worrying trait is his apparent thirst for nuclear war. Although he is voted into office in all the timelines to date, Ruby's now-defunct future from "73 Yards" appears to be the only one where his tenure was so brief that he wasn't able to make much of an impact. However, now that Ruby and her mysterious future self will no longer be around to stop him, another version of the 2040s will surely bring Roger ap Gwilliam back as a major threat.

3 The Midnight Entity

The return of a Tenth Doctor villain took everyone by surprise in "The Well"

Doctor Who season 15, episode 3, "The Well," gradually revealed itself as a sequel to a David Tennant adventure from 18 years earlier. First seen in 2008's "Midnight," the Doctor's nameless enemy makes a shock return three episodes into Gatwa's second run as Fifteen. I'm sure I'm not alone in never expecting the villain to come back to Doctor Who after Tennant's era, given how beloved "Midnight" was, and the risk involved with legacy sequels. The unconventional antagonist had other ideas and found its way back to the franchise for a rematch with its ancient nemesis.

"Midnight" ended with the implication that the monster was suitably dealt with for good, and "The Well" initially teased the same. One of the biggest differences between the two endings is that "The Well" reveals that the unseen entity left the planet's surface. There is even the possibility that there was always more than one of the monsters, and that the one that escaped is a new character - although this is unconfirmed. Theories about multiple entities aside, I'd say it's pretty likely that it won't be as long this time around before Doctor Who's Midnight Monster returns.

2 Conrad Clark

Ruby's deceptive boyfriend ends "Lucky Day" with a worrying opportunity

Jonah Hauer-King's Conrad Clark falls into a similar category as Roger ap Gwilliam in that they both appear to be just regular human characters. Villains that fall into this category rarely cause much of a viable threat to the Doctor, but Conrad is among the minority here. Instead of facing advanced weaponry or the direct destruction of the Earth, the Doctor finds himself at the center of a damaging conspiracy theory, formulated by Conrad, that suggests alien life is a hoax to keep the public afraid and in line.

Conrad's group of conspiracy theorists is called Think Tank, the success of which probably has a hand in the future rise of Roger ap Gwilliam's Albion Party.

Conrad ends "Lucky Day" in a jail cell for his violent actions in the name of trying to out Mrs. Flood (Anita Dobson) frees him just before Conrad's debut episode ends, so there is no way we have seen the last of Jonah Hauer-King's frustratingly stubborn character.

1 Kid

The vengeful Hellion is clearly ready for a rematch with the Doctor

The Corporation is responsible for the death and destruction of the world of Hellia, as revealed in "The Interstellar Song Contest." To make their job easier, the Corporation presumably started the smear campaign against all Hellions, painting them as the monsters of the galaxy. As far as villain origin stories go, Kid's, as a Hellion, is immaculately written. Freddie Fox's character fails in his genocidal plot to wipe out all three trillion viewers of the episode's titular Corporation-sponsored event, but he at least survives past the end of the episode.

KID: "I'll see you again, Doctor."

THE DOCTOR: "And I'll be ready, Kid. Believe me, that ice that you put in my heart, I think it's still there. I think it'll be there forever, now. So you take care."

Doctor Who season 15, episode 6, "The Interstellar Song Contest."

Kid's final exchange with the Doctor essentially promises the pair will meet again, and Gatwa's character is forever changed by their meeting and appears to relish the thought of a rematch. The Doctor's dark connection to genocide in his past brings out the most worrying elements of his character when awoken, and Kid is the perfect catalyst to remind the Time Lord of everything he has lost, done, and all the other things he would rather forget. Kid could be a great recurring Doctor Who villain, if used correctly.