Sea Devil

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. As colonies awoke from hibernation, these one-time rulers of the Earth attempted to reclaim their planet.

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

The Silurians were related to the Sea Devils, though they were genetically divergent enough to create problems for the offspring of such matings. (MA: The Scales of Injustice)

Culture
The Sea Devils were known to worship the Great Old One known as Dagon as their god. (NA: All-Consuming Fire) They were determined to retake the planet from the humans. They held an unwavering view that, as the original rulers, it would always be their right to do so. (DW: The Sea Devils)

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 thousands of underwater colonies, filled with millions of their kind. These bases appeared to be carved out of rocks and were generally covered in algae and seaweed. These colonies could be reactivated en masse with a sonic signal.

They used a less effective 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 large supplies of weaponry in these bases. They typically used small, round, side arms. (DW: The Sea Devils) During their invasion of Sea Base 4, they made use of a larger version of the device 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 awoken. (DW: The Sea Devils)

At some point before 2050, the Sea Devils were one of the many races attacked by the Anubians. (K9TV: Curse of Anubis)

In the mid-20th century, a group of Sea Devils were awoken by the Master. He attempted to persuade them to reclaim the planet from the human race. Despite the Third 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)

In 1983, Sarah Jane Smith and K-9, while visiting Warren Martyn's archaeological expedition in Egypt, discovered an underground city of Silurians and Sea Devils. Sarah Jane opened diplomatic relations with them, and on her return to England, contacted the Brigadier, who was willing to make amends for his earlier mistakes. (DWM: City of Devils)

A 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)

By the 26th century, the inter-species conflicts appeared to have come to an end. Silurians and Sea Devils were accepted into Earth society, and the term "Earth Reptile" was apparently popularized among humans. (NA: Love and War) In the 30th century, the Earth Reptiles were part of the Earth Empire and were considered full members of that government, due to the fact that they were an Earthborn species. (NA: So Vile a Sin) In the 32nd century, it became illegal to trade in Earth Reptile pituitary analogue extract on the planet Dramos. (MA: Burning Heart)

At some point around the 26th century, a number of Sea Devils as well as humans colonized the planet Chosan, which was being attacked by Calabraxian terrorists. This prompted the Earth Reptile Council to ask the Braxiatel Collection for aid which they sent in the form of Bernice Summerfield. Her time there revealed that the ocean planet possessed a sentient protein in the waters which had began to infect the water-dwelling Sea Devils.

The entities attempted to possess the Sea Devils and use them as an army against the humans but faced difficulty in integrating themselves into the host's biology. This led to a number of mutations. They were ultimately successful and managed to possess the Sea Devil Lurnix as a host. They tried to have Lurnix lower the security grid and infect all the Sea Devils to use as an army.

However, Bernice Summerfield was successful in evacuating the colony and detonating a bomb at Chosan, ending that threat. As a result, the Sea Devils were forced to abandon the Chosan colony due to the threat posed by the alien protein. (BFBS: The Poison Seas)

In the 101st century, the Earth Reptiles were part of the Union. (MA: The Crystal Bucephalus)

Alternate Histories

 * In one alternative version of the 1990s, the Doctor having died during the Wenley Moor incident, the Silurians ruled Earth unchecked. The Sea Devils served them as underwater soldiers. (NA: Blood Heat)

Undated Events

 * During the Last Great Time War, a Sea Devil was imprisoned by an unknown force. (IDW: The Forgotten)