Ever since their 1966 debut, the Cybermen have been some of the most iconic monsters in the decades-long history of theDoctor Whoseries. Between their striking designs, eerie electronic voices, and chilling lack of emotion, it’s easy to see why they’ve stuck around for the better part of 60 years.

However, the Cybermen have long occupied a strange place within the narrative of the series. Despite being beloved antagonists in their own right, they’ve often found themselves playing second fiddle to more prominentvillains like the Daleksor the Master — especially in the modern series. However, there’s one specific story from the very end of Steven Moffat’s time as showrunner that put the Cybermen back in the spotlight, reminding viewers of just how terrifying, fascinating, and thought-provoking they can be. That was the Series 10 two-part finale, “World Enough and Time” and “The Doctor Falls.”

Mondasian-Cybermen-Doctor-Who

RELATED:Doctor Who: What Other Past Companions Could Return?

The Genesis of the Cybermen

“World Enough and Time,” starring Peter Capaldi in one of his final adventures as the Twelfth Doctor, takes place on a colony ship from the planet Mondas — the home of the original Cybermen from 1966’s “The Tenth Planet.” Shortly after arriving on the ship, the Doctor’s companion Bill Potts (Pearl Mackie) is separated from him, and ends up living among the Mondasians on thelower levels of the ship. And in the process, Bill bears witness to the first stages of the Cybermen’s creation.

The entire episode serves as a massive throwback to the original Mondasian Cybermen. First and foremost, there’s the return of the Cyberman design from “The Tenth Planet,” with its clunky computer-like chest piece, skin-tight mask, and dark, hollow eyes. Though it may look clunky and silly at first, the design manages to be surprisingly creepy in practice. The Mondasian Cybermen have an ominous, off-putting vibe, with their almost-human appearance placing them firmly in the uncanny valley. The design is even foreshadowed by the look of the partially-converted Mondasian patients, whose heads are completely covered by the same white masks that they’ll later retain as Cybermen.

Promotional image of World Enough and Time, an episode from the TV show Doctor Who.

“World Enough and Time” is a horror story as much as it isa science fiction adventure,with the concept of the Cybermen being utilized to frightening effect. However, the horror of the episode comes not from the physical threat posed by the Cybermen, but the disturbing nature of cyber-conversion. In one early scene, a partially-converted Mondasian sits helplessly in place as it repeats the word “pain” over and over again in its electronic monotone. To be a Cyberman is to be trapped in constant pain, and only their Emotional Inhibitors prevent them from succumbing to the overwhelming agony.

But of course, that’s only where the terror begins. In the episode’s biggest twist, “World Enough and Time” ends with the reveal that Bill herself has been transformed into a Cyberman. The Doctor was too lateto save his companion,and Bill is now trapped in a cold cybernetic shell, seemingly forever. The episode ends with the visual of a single tear falling from the empty eye socket of Bill’s Cyberman form — a chilling reminder that each and every one of the Cybermen were once human beings. Before they became heartless, faceless, killing machines, they were once people with thoughts, feelings, hopes, dreams, and loved ones. And now, the Doctor’s closest ally has become one too.

Technological Terror

However, Moffat’s understanding of the Cybermen doesn’t end with what makes them scary. “World Enough and Time” also explores what drove the Mondasians to become the Cybermen in the first place. The Cybermen weren’t born outof a desire for poweror conquest, but merely out of desperation to survive. Over time, the colony ship had become inhospitable, forcing the Mondasians to evolve themselves into beings capable of withstanding their new environment. In order to endure, they chose to purge themselves of all weakness, even if it meant giving up emotion. To the Cybermen, sacrificing individuality for immortality is an upgrade, and they wish to share their gift with the rest of humanity — whether they want it or not. In that sense, the Cybermen are driven by a form of altruism, albeit one devoid of humanity.

It’s not just the Cybermen’s motives that interest Moffat either. In the story’s second part, “The Doctor Falls,” a new theory is proposed regarding the Cybermen’s origin.Early in the episode,the Doctor states that the Cybermen can’t be traced back to a single shared beginning. Rather, they’re the result of parallel evolution, being created independently countless times on countless worlds throughout history. “They happen everywhere there’s people,” the Doctor says — in other words, any human world with sufficiently advanced technology will inevitably produce Cybermen. It’s an idea that’s as unsettling as it is fascinating.

But perhaps most importantly of all, “The Doctor Falls” features the Cybermen taking back their place as main antagonists. In their previous appearance in Series 8’s “Death In Heaven,” the Cybermen served as subservient drones to Michelle Gomez’s Master, aka Missy. Two seasons later, it seems as if the Cybermen will once again serve as the Master’s flunkies, with Missy now accompanied by the unexpected returnof John Simm’s Master.However, the Cybermen quickly turn on the villainous Time Lords, reasserting themselves as worthy big bads in their own right. In the episode’s climax, one Cyberman even lands a fatal blow on the Doctor, forcing him into regeneration — a feat that few of the Doctor’s foes have accomplished.

The two-part story of “World Enough and Time” and “The Doctor Falls” isn’t just one of the best Twelfth Doctor stories. It’s also one of the greatest depictions of the Cybermen, not just in the modern series, but in the entireDoctor Whofranchise. After years of being overshadowed by other villains, these legendary antagonists finally gota shot at redemption. When written well, the Cybermen are some of the most compelling, frightening, and even tragic villains in the Doctor’s entire rogues’ gallery. And for proof of that, look no further than this Series 10 two-parter.