The Bestiaries of Déchiré - Creatures of the Sea

Fish/sharks/rays, whales/dolphins, invertebrates-corals/jellyfish/octopi/sponges, plants, etc - As elsewhere.

Meth'dai/Merfolk/Sea-Elves - Terms used interchangably, for the most; though there does seem to be a particular tribe which most resembles the elves of land. The Meth'dai (Meh - th[a] - dah - ee) carry the traditional features of mer-folk, with the upper halves of humans and the tails of fish or whales. Those of the fish-tail variety (Meth'dai Ha-ra) are not limited in color, pattern, or frill; those of whale-tail type (Meth'dai-ayet) are nomally grey, brownish, or black. A number of the Meth'dai are said to have voices of painful beauty, rivalling the tales of the Siren. Maidens of the Meth'dai (and sometimes their men as well) will bring wrecked sailors to shore if they are close enough. If not, the bodies which sink into their lands are laid to rest in the remnants of ships gone long before, and the souls of the departed honored at periodic feasts.

Sea whips - A long, serpentine creature bearing fangs and fins. The spiked tail is laden with a highly toxic poison; sailors on a ship without either a healer or a mage are almost certain to die if stung by a sea whip.

The Siren - It is unknown whether the Siren is an actual resident of the seas, or simply a legend whose origins are lost in time. Said to be a woman of exquisite beauty, the Siren lures her mates to her hall by means of an enchanting song; where they drown during the act of intercourse and are eventually devoured. There is a chanty known in nearly all languages and all cultures which is specifically devoted to warding off the Siren on journeys by sea.

Asunder - The Bestiaries of Déchiré