Commonly called Silurians, the creatures have also been referred to by other names. The terms "Silurians" and "Eocenes" are human misnomers, as the creatures date from a period between those times.
In some tales, Sea Devils worship the Great Old One Dagon as their god. They are determined to retake the planet from the humans. They hold an unwavering view that, as the original rulers, it would always be their right to do so.
Sea Devils look somewhat like humanoid turtles or plesiosaurus. They have beak-like mouths, large eyes, two fins on their head and long necks. They have three webbed digits on their hands and feet. Their skin tones come in a variety of shades, including green, blue and orange. They are much tougher than humans, since they need to survive the crushing depths of the ocean. Sea Devils communicate in a language like SONAR, but they can speak human languages in a whispering, rasping voice. A Sea Devil's skin is apparently slimy to the touch.
The Sea Devils were more advanced than the humans of the 20th century when they went into hibernation. They had thousands of underwater colonies dotted across the globe, each filled with millions of their kind. These bases were carved out of rocks and were generally covered in algae and seaweed. The colonies could be awoken en masse through the use of a sonic signal.
The Sea Devils had stockpiles of weapons in these bases. They typically used small, round, side arms. During their invasion of Sea Base 4, they made use of a larger version of the device to cut through the doors.
Common Sea Devils wore a blue, gauze-like dress. The elite soldiers in the 2084 invasion wore thick black armour reminiscent of samurai armour.
Figures are from Black Tree and were kindly painted for me by Robafett.