The Fantasy Review’s brief history of the Sea Devils. Everything you need to know before watching The War Between the Land and Sea, the latest Doctor Who spin-off!
The Sea Devils have been around in Doctor Who for a long time – since Jon Pertwee’s era. They are the ancient, amphibious cousins of the Silurians, once rulers of the planet.
The War Between the Land and Sea comes out on BBC iPlayer and Disney+ on 7th December, 2025.
Ancient Rulers of Earth
Before humanity ruled the Earth, it was the Silurians who roamed the land, while the Sea Devils dwelled in the oceans. These ancient races were a united civilisation, overseen by the Triad.
The Sea Devils are an amphibious reptile humanoid species with thick skin. They speak in whispered voices or with sonar-based communication.
Their astronomers predicted a major disaster that could wipe out all life on the planet, so both species hid underground or underwater, locking themselves away in hibernation chambers.
The disaster they predicted never came, however, leaving the Silurians and Sea Devils to sleep for millions of years while humanity took over the planet.
Before hibernation, they were peaceful scientists and explorers, for the most part, only resorting to violence if completely necessary.
The Sea Devils on TV
The Sea Devils (1972)
We first meet the Sea Devils in The Sea Devils serial with the Third Doctor (Jon Pertwee) and his companion, Jo Grant. The Master encourages the newly awakened Sea Devils (under a naval sea fort) to reclaim the planet and destroy humanity.
The Doctor works tirelessly for peace, however their clash with UNIT and humanity does not end well. With a mix of the Master’s meddling and the Sea Devils’ bitterness, plus humanity’s aggression, tensions escalate to the point where the Doctor is given little choice but to sabotage the Sea Devils’ base to prevent global war.
In The Sea Devils we are introduced to this species and learn:
- They have a noble culture, firm in traditions, with a rigid culture
- Their technology is advanced
- They are related to the Silurians, but this does not mean they always get along
Warriors of the Deep (1984)
The Fifth Doctor (Peter Davidson) has a run-in with The Sea Devils, along with Tegan and Turlough, in the year 2084. Here the Doctor finds the Sea Devils allied with the Silurians against humanity, with a plan to take back the Earth.
Again, the Doctor is given no choice in the end but to kill many Sea Devils and Silurians with Hexachromite gas, as peace was impossible.
“There should have been another way.” – Fifth Doctor, Warriors of the Deep (1984)
Legend of the Sea Devils (2022)
Brought back with a new design, Jodie Whittaker’s Thirteenth Doctor (with Yaz and Dan) go up against some Sea Devil pirates (first seen in expanded media) in Legend of the Sea Devils (2022).
Here the Sea Devils are shown to be ruthless and keen to reclaim the planet from humanity, however, once again, the Doctor stops them.
The War Between the Land and the Sea (2025)
The upcoming five-part series (created by Russell T Davies) is a Doctor-lite series with links to Torchwood, focusing instead on UNIT as they come up against the Sea Devils.
From what we have seen of trailers, information released by the showrunners, and other marketing materials, The War Between the Land and the Sea promises to cover some familiar ground:
- The Sea Devils want to reclaim the Earth
- Morally complex themes over who has the right to the planet
The only difference being, there is no Doctor this time. UNIT are on their own.
