The Black Mermaid is the major villain of The Calling of the Ocean.
The Black Mermaid was originally just a powerful mermaid, until she decided that she wanted to rule the world. She changed into a nightmarish, white-skinned and black-haired and -tailed mermaid. Collecting others who also lusted for power, she called them all the Black Mermaids and began traveling the oceans, trying to conquer the world.
Then a human girl transformed into a mermaid, fought and defeated her. The battle cost the girl her humanity, but it transformed the Black Mermaid's spirit into gas. She spent a long time re-forming, growing in power, and planned to flood the Earth to destroy humanity.
Later, she discovered her newest opponents, Lucy and Jack, and began telepathically harassing Lucy. While they were out potion-hunting, she found and chased them, but they escaped. By this time, she'd already put their village in a force field, keeping the sun permanently visible. Taking over Lucy's body, she informed Jack that she'd expanded her plan to destroying the universe, and left to do just that.
Powers and AbilitiesEdit
The Black Mermaid is said to have the power to move land and control the sea, and is developing the ability to possess others, as she prepares to take physical form again. She has also demonstrated telepathy, both to send messages and apparently to possess a dog--or put someone else's mind in the dog's body. On the last day of the month, she can possess Lucy's body.