Doctor Who Spinoff Reveals Why Sea Devils Look Different in New Series

The Sea Devils have a dramatic new look. This change was revealed in the new Doctor Who spinoff, The War Between the Land and the Sea. The first episodes launched on BBC iPlayer on December 7. UK fans got their first look at the redesigned aquatic villains.

The redesign had sparked fan theories for months. Many believed it was a simple visual update. The show’s first episode, however, provided a clear in-universe explanation.

UNIT’s Discovery Confirms a New Subspecies

Early in the first episode, a UNIT officer makes a key statement. He examines a deceased Sea Devil and reports his findings. His line is deliberately specific: “It’s the first time we’ve seen one exactly like this.”

This implies UNIT has encountered other types before. The original classic-era Sea Devils are likely a related species. According to the BBC’s coverage, this allows the classic design to remain canonical. It is simply a different form of the same broad category of being.

The new species is given a scientific label. They are called Homospondyl Erectus. This distinguishes them from the Sea Devils seen in past Doctor Who stories. The creative decision expands the franchise’s lore instead of erasing it.

A Diverse Underwater World Emerges

The spinoff introduces more than just one new type. Another subspecies, called Piscimorpha Grandis, is shown. This creature is far more fish-like than its bipedal cousins. It appears alongside the new Sea Devils in a containment tank.

Furthermore, Gugu Mbatha-Raw’s character Salt is revealed. She is identified as the first Homo Amphibian. This suggests a vast and varied ecosystem of intelligent life under the sea. The collective term for all these beings is “Homo Aqua.”

This retcon makes logical sense. Most of Earth’s oceans remain unexplored. It is plausible that multiple sentient species could evolve in isolation. The show uses this to explain the visual changes.

The new Doctor Who spinoff has cleverly expanded the Sea Devils’ legacy. It introduces a whole family of Homo Aqua species. This bold move keeps the classic monsters relevant for a modern audience.

Info at your fingertips

Why do the Sea Devils look different in the new show?

The show introduces them as a distinct subspecies called *Homospondyl Erectus*. A UNIT officer states it’s the first time they’ve seen this specific type, implying other varieties exist.

Are the original classic Sea Devils still canon?

Yes. The dialogue suggests UNIT is familiar with Sea Devils, just not this specific kind. The original design is considered a different, but related, type of Homo Aqua.

What other new species are shown?

The episode also features *Piscimorpha Grandis*, a more fish-like creature, and introduces the first *Homo Amphibian*, played by Gugu Mbatha-Raw. All fall under the Homo Aqua category.

Where can I watch the new spinoff?

The series, *The War Between the Land and the Sea*, is now streaming on BBC iPlayer in the UK. It is scheduled to arrive on Disney+ in 2026 for international audiences.