Sea Devil

The Sea Devils were a race of amphibious Earth Reptiles. The Sea Devils, like their land-based cousins the Silurians, were scientifically advanced, and lived during prehistoric times in an aquatic civilization.

Appearance
Sea Devils looked somewhat like humanoid turtles or plesiosaurus. They had beak-like mouths, large eyes, two fins on their head and a long neck. They had three webbed digits on their hands and feet. Their skin-tone came in a variety of shade, including green, blue and orange. They were much tougher then humans, since they need to survive the crushing depths of the ocean. Sea Devils communicated in a language like sonar, but they could speak human languages in whispering tones. (DW: The Sea Devils)

The Silurians were closely related to the Sea Devils, though they are far enough apart genetically to create problems for the offspring. (DW: The Scales of Injustice)

Technology
The Sea Devils were more advanced than the Humans of the 20th century when they were forced to go into hibernation.

The Sea Devils had millions of underwater colonies, filled with thousands of Sea Devil. These bases appeared to be carved out of rocks and a generally covered in algae and seaweed. These colonies could be reactivated on mass, usually with a sonic signal. They use a less effective method hibernation technology in these bases, leading to some muscular degradation when they were brought back. (DW: Warriors of the Deep)They also used special orange capsules to transport land-dwelling creatures. (DW: The Sea Devils)

The Sea Devils had a large supply of weaponry in these bases. The Sea Devils commonly use a small, round, hand-held weapon. (DW: The Sea Devils) During their invasion of Sea Base 4, they made use of a larger version to cut through the doors. (DW: Warriors of the Deep)

Common Sea Devils wore a type of blue, gauze-like dress. (DW: The Sea Devils) The soldiers in the 2084 invasion, being elite soldiers, wore thick black armour somewhat reminiscent of samurai armour. (DW: Warriors of the Deep)



History
While the Silurians ruled the Earth, the Sea Devils were used as foot soldiers. When the Moon was coming dangerously close to Earth, they also went into their colonies to hibernate. After millions of years, some of the colonies were awaken.

They were first awoken in the mid 20th century by the Time Lord known as the Master. He attempted to persuade them to reclaim the planet from the human race. Despite the Doctor's efforts to convince them otherwise, the Sea Devils eventually decided to go to war, and the Doctor was forced to destroy their base. (DW: The Sea Devils)

A different colony of Sea Devils were awoken in 2084 by the Silurians. They were sent as shock troops to invade Sea Base 4. Though they were better prepared, they were all killed by the Hexachromite gas used by the Doctor. (DW: Warriors of the Deep)


 * Curiously the creatures used the terms "Silurians" and "Sea Devils" to refer to themselves, despite these terms previously being purely human phrases. This may be translation from their true names by the TARDIS.