Mermaids and Merman are things of myths and legends but in truth they are very real. They remain hidden to the world and humans in general. Sometimes a human may catch a glimpse of one but most chalk it up to seeing things or an overactive imagination.
What helps with this is that the merfolk population is extremely low and therefore easy to hide in such a massive amount of space that makes up the oceans of the world. That isn’t even considering the small underground communities that merfolk has made in cave systems which no human would ever find.
With such a small population the risk of inbreeding and the genetic defects which can come from that was discovered long ago by the merfolk communities.
With that in mind, a ceremony was developed. A ancient ritual using the magics given to them by the gods and goddess of the ocean.
When a mermaid or merman reaches their 21st birthday they are allowed to travel to the surface, to get near to humans and “find” a mate.
Finding a mate can take many forms, some use magic to call a human to them. This is where humans get the story of the siren luring humans to their doom. The magic used in the song almost always finds a human ready to leave humanity behind and accept the sea by becoming a mermaid or merman. This however removes the ability of the mermaid or merman to pick their future mate. The song does that for them.
Others risk transforming themselves briefly into humans to talk to them. To get to know a human before transforming them. This however is extremely risky since young merfolk tend to know next to nothing about human world and if saltwater gets on them, they can transform back and they can only remain on shore for a day. However this does give them a chance to talk to the human and get to know them before the ritual is done or not done.
Still others watch a group of humans and pick out the one they like and pray that they choose one who will accept the sea and themselves. The ones who choose this tend to pick humans they find attractive or interesting. This also has the highest rate of failure for if a human refuses the transformation into a mermaid or merman they are killed.
Once a human is selected, they will be transformed into a mermaid or a merman. During this process any human not willing to accept the sea or whom is not in “love” with the mermaid or merman transforming them will die. The transformation process can and has transformed people’s genders turning human man into mermaids and human women into merman.
Once transformed the new couple return to their ocean home to make a life together under the sea. Gay and Lesbian relationships are fully accepted under the sea and even poly relationships are common enough even if group transformation is rare.
Some mermaids and merman have to take the ritual to find a mate multiple times, sometimes the song fails, the one they pick dies or they fail to find one they are interested in. Not everyone comes back home with a new mate. Even those who have had a mate can go out and find a new one in a special ritual if their mate has died.
To the humans, they pass off those who disappear at sea as unfortunate accidents and go on with their lives.
A mermaid or merman is currently carrying out the ritual to find a mate who they are and how do they go about finding a new mate?