Selkie

In their true form selkies are almost impossible to tell from seals. A close look reveals slightly webbed hands in place of front flippers and legs instead of a tapering rear. Once a month a selkie can take human form for about a week. As humans they are strikingly beautiful and have broken many hearts, and their eyes are always vivid emerald green or pale, startling blue. The change is not magic, so only spells such as true seeing reveal it, though odd habits and a fondness for seafood may also give them away.

Weapons slow them in the water, so 90% of selkies met underwater carry none. They bite when cornered but would rather use their great swimming speed to escape a superior foe. On land they sensibly carry human weapons, usually swords salvaged from shipwrecks.

Selkies call the human world the 'overworld' and visit mostly out of curiosity, though sometimes they are sent to buy needed goods or information. They live only in cold water, in salt and fresh varieties, building lairs in huge submerged caves with both flooded and air-filled chambers; their young must live in air for about the first year. Females usually outnumber males, since males do the hunting and gathering in dangerous waters, but home and provider roles are equally honored and neither sex has special privileges.

They love exploring wrecks, and most communities hold some treasure, especially pearls, kept solely for trading with the overworld. Frequent visitors develop a taste for jewelry and stand out at once, and they make the best go-betweens; selkies can be hired and know a bit about human ways. Any magic they find is claimed by the community for its defense.

A community's venerable leader has daily use of cure disease, augury and cure light wounds (one per round), plus control weather and weather summoning weekly. Selkies believe the sea would punish them for using such powers wickedly.

Omnivores, they eat fish, shellfish, crustaceans and seaweed, and those who visit the surface often enjoy human food too. Fine wine affects them strongly, since no such drink exists under the sea. They harvest only what they need and lobby hard when human activity threatens their waters, having learned that a few pearls dropped in the right places get results. Luckily their pelts are worth little to humans, so they face no enemies beyond those common to seals and other sea dwellers.