While giving Radio Times magazine a tour of the set for the Doctor Who spin-off The War Between the Land and the Sea, showrunner Russell T Davies explained the sea-dwelling race familiarly known as “Sea Devils” prefer to be called “Homo Aqua“.

“It’s racist to say Sea Devil,” Russell T Davies told RT, with a twinkle in his eye.

In the premise of the spin-off, it’s the humans who are the villains. After years of polluting the oceans, humankind finds itself in conflict with Homo Aqua. It’s up to human negotiator Barclay (Russell Tovey) and aquatic ambassador Salt (Gugu Mbatha- Raw) to discuss terms in underwater peace talks on the sea floor. The Homo Aqua base is described as a twisted, tendril-strewn dome.

“I think every writer in the world is thinking, how do you write about the climate crisis?” Davies continued. “We’re already in a climate war. This just dramatises it.”

Davies explained that fans shouldn’t expect the “deliberately tougher” spin-off to be like the main show — or for the TARDIS to turn up.

Written by Russell T Davies and Pete McTighe, The War Between the Land and the Sea will air on BBC iPlayer and BBC One in the UK in December 2025, and exclusively on Disney+ outside of the UK (where available) in 2026.