Geryas
Geryas (plural and singular) are monstrous seafaring reptiles that reach lengths of up to 60 feet. Their bodies are thick and barrel-shaped with warmth-giving blubber and fat. The geryas is possessed of a long, whiplike tail and an equally long neck, at the end of which is a head possessed of rows of razor-sharp teeth. Instead of legs, the geryas has adapted flippers for its aquatic environment. Nevertheless, it is still capable of waddling about on the land, albeit somewhat clumsily.
At least two geryas are known to exist in Achaea. The first dwells within caverns at the feet of the ocean cliffs east of Rheodad. The second, either a geryas or else a species closely resembling one, dwells within the lowest levels of the sewers of Mhaldor. However, tales of these creatures haunt the nightmares of many sailors across the world, and as such there are doubtless many more lurking within the vast uncharted seas.