Sea serpents
Sea serpents are great sea snakes with sinuous coils which swim beneath the surface of oceans of Achaea to come upon ships unawares. Their bodies can be as long as a league in length, their iridescent fins frilling their undulating bodies and enabling propulsion through the deep waters of the seas. Akin to their landbound cousins, but much multiplied in size, the heads of sea serpents are snake-like in shape, but larger than trolls. Their black eyes stare from blue mottled scaling, and great forked tongues taste the tidal spray, flickering between terrifying fangs.
The formidable jade sea serpent of Phereklos is one such example, a gentle creature despite its fearsome appearance. It resides in the underwater ruins of Phereklos where it sometimes supplements its usual diet of ocean animals with occasional adventurers who provoke it.