So this is an rp based on an idea for a book I am currently attempting to write:
When Merpeople come of age they get a "Wander Year", a year they can get legs and live on land as a human. During this time they have their siren song, beautiful voices that captivate people (not mind control just people can't help but listen), a magical item (necklace, ring, ext) that gives them their legs, funds from jewels gathered in preparation for their Wander Year and beauty that draws people to them.
Downsides are if they get wet their tails come back until they are dry. If they stay dry too long they can die and the full moon takes over merpeople and compels them to return to the water until it passes.
You can be a merperson or a human. But beware: break the heart of a mer and you are cursed to die the next time you touch the sea...
Any interest?