Mermen (or Nereids, as they call themselves) are a really strange race, even with the high diversity of the world. Their appearence is smilar to continental humanoids, but their body below their hips is fish-like. Also, about their hair and skin colour.... in addition to the "traditional" human hair (black, brown, red, blond) and skin (black, brown, yellow, white) colours, their hair and skin can be also ocean-blue and sea-green.
They live in water, more specifically: warm seas. As a race of magical origins, all mermen can use water magic and (without exceptions) are strong with it. This high concentration of magic allows them to shapeshift, to adopt a fully humanoid body for a longer period of time. All inviduals of this race is capable of doing it, and this might be an evidence to the hypothesis that they were once a fully humanoid race later getting adapted to marine life, altrough no official records provide evidence to that. Anothere evidence might be that they actually wear clothes and jewelry (mainly bracelets). But there are also some counter-evidences: despite their continental relatives, they are incapable of crossbreeding with them. Also, the beauty of the nereids is a worthy competitor of a high elf's beauty, and somehow their voice also "summons emotions": a nereid's angry speech can calm down people (or sometimes scare them), their sad speech can make you uncertain about things, their happy speech makes you feel happier, etc.
They are very agile in their human forms, but only after learning how to walk and swim in human form properly. Their aliment is usually more chaotic than other races'. They know weapons, too, but they prefer to use weapons which are useful on both surface and underwater, such as spears, harpoons and tridents. We can also find their flourishing underwater kingdoms which have very different norms from surface ones, but lone nereids aren't rare either. All of their "little civilizations" have the same religion: they believe in nameless gods of their own pantheon, and they usually do not deny the existence of other gods, they merely deny their subordination to these foreign deities.
One thing we can notice about all nereids is their scepticism about continental civilizations, which makes them reluctant to accept continental titles and makes them only seemingly accept continental laws, with the exception of port cities where laws are less harsh (to them). this is why many nereids live in pirate heavens such as Gabyr, and many also join the pirates, altough they often stand out with their more patient and less sadistic characters, they are welcomed sailors regardless, due to the advantages of their magically "amphibious" abilities.
They sometimes appear in their natural form on the southern coastline of Artongrach, but to the north (such as Etrand) they are counted as tales, usually rather as sea demons who lure sailors into the the sea with their beautiful but delusive singing. On those parts of the world, people never even heard of their shapeshifting abilities. For these reasons those nereids who rarely happen to visit these lands don't really reveal their true identities, naturally unwilling to test how much the zealous followers of Titanius might want to purge them.
Enabled aligment: any, with the exception of Lawful Good and Lawful Evil