Mermaids are one of the 6 types of PARA, and generally the type that are best accepted by society.
To be turned into a Mermaid is to be Underwaterfied. After being bitten, the individual finds themselves very thirsty, with no amount of water able to quench their thirst. They are unable to sleep until they are fully submerged in an ocean (or sea) - as soon as they are submerged, they sink to the bottom of the ocean (or sea) they are in, fall into a three day sleep, and awaken with a tail where their legs used to be.
The colour of a mermaid's tail is determined according to the PARA Colour Chart. The colour of a mermaids hair is the colour that their eyes were before being Paraformed. The colour of a mermaid's eyes is the former colour of their hair.
Angels (due to their vulnerablility to water) are unable to become mermaids. Fairies are able to become mermaids, however their wings are instead tranformed into fins, enabling them to swim up to twice as fast as a regular mermaid. The colour of an ex-fairy mermaid's skin is generally the same as that of their original skin colour, unless they become a Strompet, in which case it becomes a very dark blue.
Mermaids are unable to breathe or speak underwater: just like terranean persons are unable to breathe or speak underwater. Again, like terranean persons, a spell can be cast enabling them to both breathe and speak above water, however as all PARA are unable to use magic of any kind, they rely on others for above-water communications.
Perhaps as a result of this, mermaids tend to cut off communication with above-water beings completely. Occasionally, when they have had a war with another underwater city, they will "recruit", by sending their most attractive up to the water, and luring pirates of both genders to jump into the water, at which point they will bite them and cause underwaterfication. This job is known as being a "Siren" to the mermaid communities.
There are three major mermaid "tribes" - Leira, Dofluna, and Sastia. Though these mermaid tribes have many cities, there are many more mermaid cities which are completely independent of any such affiliations, and there are several other, minor "tribes" as well, most noteably the Strompets, those who work for whoever is in charge of the Fairy city of Strom at any given moment.
The most revered role in mermaid society is that of the "Abgal" or teacher. Abgal will teach from dawn to dusk, not stopping to eat, and then at night they are treated like kings, offered feasts and their choice of mates.
Both male and female mermaids are referred to as "Mermaids". Many Mermaids are Mermans, worshippers of Merma, God of the Sea.
Mermaids have no regenerative abilities. In fact, when a mermaid is cut or otherwise injured, they cannot be healed except for by magic. As such, those who are damaged, either in a battle with other mermaids, land-dwellers or creatures of the sea (or, rarely, by accidents: aware of this weakness, mermaids generally do all that they can to avoid such accidents) generally die within a day, unless they are lucky enough to know someone capable of casting healing spells.