Theralind's Brood

Theralind was the beloved of Corduin of L’Anguille, first Duke and Grail Companion. Legend has it she was transformed into a hideous sea-monster by a jealous hag, but her natural virtue triumphed and she now guards the port. The fierce, unpredictable storms that lash the coast are said to be the result of her grief, and it is true they almost never strike L’Anguille itself nor the shipping channel leading to the port.

The monsters referred to as Theralind’s Brood are certainly hideous, but they seem to have no natural virtue. They are serpent-like, though their heads are best described as like scaly horses with fangs. They have two clawed arms but no apparent hind limbs. The brood seem to revel in the most dangerous currents and show no hesitation in attacking boats or even ships. They can leap from the water to reach the deck of a vessel (scholars report that they can survive for up to half an hour on land) and fight just as viciously there. Some think that they are the adult form of the carnivorous fish in the Sannez. At any rate, they have never been seen outside the Gulf of L’Anguille.

Source

 * Warhammer Fantasy RPG 2nd ED -- Knights of the Grail (pg. 44).