Sea Devils

"It is our time!"

Once the rulers of planet Earth, the Sea Devils were a species related to the Silurians. Like their reptilian cousins, they hailed from pre-historic times and pre-dated the existence of humans. 
 
The Sea Devils looked dinosaur-like, similar a modern-day turtle. With large eyes, beak-like mouths, webbed hands and feet and green-blue skin, they were extremely well-suited to their oceanic habitat. They were strong enough to live at the very bottom of the ocean and, though they could speak human languages, they mainly communicated by sonar. 
 
The Doctor first met the Sea Devils when the Master was trying to make an alliance with them. After some deep-sea building work brought them out of a long hibernation, the Sea Devils left their base and emerged on dry land. They eventually retreated after encountering the Doctor and Jo Grant, but were then sadly caught in a seemingly-fatal explosion. 

The Thirteenth Doctor, Yaz and Dan met the Sea Devils once again when the infamous Madam Ching awakened Captain Marsissus and his pirate crew in 19th-century Asia. Fighting for the future of the planet, they eventually defeated these swashbuckling creatures of the deep with the help of new friends Ying Kei and Ji-Hun.